<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/net/phy, branch v7.2.4</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>net: phylink: correctly validate returned PCS in phylink_inband_caps</title>
<updated>2026-09-07T15:37:19+00:00</updated>
<author>
<name>Christian Marangi</name>
<email>ansuelsmth@gmail.com</email>
</author>
<published>2026-08-17T21:30:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=fb4d77553841ae85bed9b2cf03351c401e871d85'/>
<id>fb4d77553841ae85bed9b2cf03351c401e871d85</id>
<content type='text'>
commit f2849b1fd059ec9b3281b771e6ac5aad9feee851 upstream.

In phylink_inband_caps(), the PCS returned by mac_select_pcs is only
checked if NULL but mac_select_pcs can also return an error pointer.

This can cause a kernel panic as phylink_pcs_inband_caps() only checks
if passed PCS is not NULL and directly dereference ops from the phylink_pcs
struct.

Use the IS_ERR_OR_NULL macro to address both case where the returned
PCS can be NULL or an error pointer and prevent a kernel panic.

Cc: stable@vger.kernel.org
Fixes: df874f9e52c3 ("net: phylink: add pcs_inband_caps() method")
Signed-off-by: Christian Marangi &lt;ansuelsmth@gmail.com&gt;
Link: https://patch.msgid.link/20260817213009.13924-1-ansuelsmth@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit f2849b1fd059ec9b3281b771e6ac5aad9feee851 upstream.

In phylink_inband_caps(), the PCS returned by mac_select_pcs is only
checked if NULL but mac_select_pcs can also return an error pointer.

This can cause a kernel panic as phylink_pcs_inband_caps() only checks
if passed PCS is not NULL and directly dereference ops from the phylink_pcs
struct.

Use the IS_ERR_OR_NULL macro to address both case where the returned
PCS can be NULL or an error pointer and prevent a kernel panic.

Cc: stable@vger.kernel.org
Fixes: df874f9e52c3 ("net: phylink: add pcs_inband_caps() method")
Signed-off-by: Christian Marangi &lt;ansuelsmth@gmail.com&gt;
Link: https://patch.msgid.link/20260817213009.13924-1-ansuelsmth@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: phy: realtek: fix EEE advertisement write on the internal PHY MMD path</title>
<updated>2026-08-10T23:05:05+00:00</updated>
<author>
<name>Oleksij Rempel</name>
<email>o.rempel@pengutronix.de</email>
</author>
<published>2026-08-06T13:47:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=202fef9bbbf5784487eec27581389c6fb97c350d'/>
<id>202fef9bbbf5784487eec27581389c6fb97c350d</id>
<content type='text'>
In rtlgen_write_mmd(), the MDIO_AN_EEE_ADV case swaps the arguments to
rtlgen_write_vend2(): it passes the MMD register number as the OCP address
and the OCP address constant as the value. The caller's value is discarded
and the write lands on the wrong register, so the EEE advertisement cannot
be configured on the affected PHYs.

Mirror rtlgen_read_mmd() and write the value to RTL_MDIO_AN_EEE_ADV.

Fixes: da681ed73fb9 ("net: phy: realtek: improve mmd register access for internal PHY's")
Signed-off-by: Oleksij Rempel &lt;o.rempel@pengutronix.de&gt;
Reviewed-by: Andrew Lunn &lt;andrew@lunn.ch&gt;
Reviewed-by: Nicolai Buchwitz &lt;nb@tipi-net.de&gt;
Link: https://patch.msgid.link/20260806134716.3511821-1-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
In rtlgen_write_mmd(), the MDIO_AN_EEE_ADV case swaps the arguments to
rtlgen_write_vend2(): it passes the MMD register number as the OCP address
and the OCP address constant as the value. The caller's value is discarded
and the write lands on the wrong register, so the EEE advertisement cannot
be configured on the affected PHYs.

Mirror rtlgen_read_mmd() and write the value to RTL_MDIO_AN_EEE_ADV.

Fixes: da681ed73fb9 ("net: phy: realtek: improve mmd register access for internal PHY's")
Signed-off-by: Oleksij Rempel &lt;o.rempel@pengutronix.de&gt;
Reviewed-by: Andrew Lunn &lt;andrew@lunn.ch&gt;
Reviewed-by: Nicolai Buchwitz &lt;nb@tipi-net.de&gt;
Link: https://patch.msgid.link/20260806134716.3511821-1-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: phy: mediatek: fix TX blink masks using the RX bits</title>
<updated>2026-08-06T12:53:16+00:00</updated>
<author>
<name>Ahmed Naseef</name>
<email>naseefkm@gmail.com</email>
</author>
<published>2026-08-04T11:35:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f684c514f7965385dae21f2535f99938e73ec1af'/>
<id>f684c514f7965385dae21f2535f99938e73ec1af</id>
<content type='text'>
MTK_GPHY_LED_TX_BLINK_SET and MTK_2P5GPHY_LED_TX_BLINK_SET are built
from the RX blink bits instead of the TX ones, so both TX masks are
identical to their RX counterparts. The TX bits they should be using,
MTK_PHY_LED_BLINK_{10,100,1000,2500}TX, are otherwise only referenced
by the per-speed branch of mtk_phy_led_hw_ctrl_set().

A TX trigger selected without a link trigger therefore programs the RX
blink bits, and the LED blinks on received traffic. The masks are also
used to decode the blink register in mtk_phy_led_hw_ctrl_get(), which
as a result cannot tell the two triggers apart: an RX-only
configuration reads back as RX and TX, and a TX-only configuration
reads back as neither.

Fixes: 7f9c320c98db ("net: phy: mediatek: Move LED helper functions into mtk phy lib")
Cc: stable@vger.kernel.org
Signed-off-by: Ahmed Naseef &lt;naseefkm@gmail.com&gt;
Reviewed-by: Andrew Lunn &lt;andrew@lunn.ch&gt;
Link: https://patch.msgid.link/20260804113511.3371248-1-naseefkm@gmail.com
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
MTK_GPHY_LED_TX_BLINK_SET and MTK_2P5GPHY_LED_TX_BLINK_SET are built
from the RX blink bits instead of the TX ones, so both TX masks are
identical to their RX counterparts. The TX bits they should be using,
MTK_PHY_LED_BLINK_{10,100,1000,2500}TX, are otherwise only referenced
by the per-speed branch of mtk_phy_led_hw_ctrl_set().

A TX trigger selected without a link trigger therefore programs the RX
blink bits, and the LED blinks on received traffic. The masks are also
used to decode the blink register in mtk_phy_led_hw_ctrl_get(), which
as a result cannot tell the two triggers apart: an RX-only
configuration reads back as RX and TX, and a TX-only configuration
reads back as neither.

Fixes: 7f9c320c98db ("net: phy: mediatek: Move LED helper functions into mtk phy lib")
Cc: stable@vger.kernel.org
Signed-off-by: Ahmed Naseef &lt;naseefkm@gmail.com&gt;
Reviewed-by: Andrew Lunn &lt;andrew@lunn.ch&gt;
Link: https://patch.msgid.link/20260804113511.3371248-1-naseefkm@gmail.com
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: phylink: put link_gpio if phylink_create fails</title>
<updated>2026-07-29T01:31:11+00:00</updated>
<author>
<name>Christian Marangi</name>
<email>ansuelsmth@gmail.com</email>
</author>
<published>2026-07-26T15:08:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0fe1e3e8f3380d7862296a73b528d164e96c76b8'/>
<id>0fe1e3e8f3380d7862296a73b528d164e96c76b8</id>
<content type='text'>
In phylink_create() if phylink_register_sfp() returns an error, link_gpio
obtained by phylink_parse_fixedlink() is never released. While this is a
very unlikely scenario, it's worth to fix/handle this.

This was present from the very first implementation of phylink but got
relevant only with the introduction of ce0aa27ff3f6 ("sfp: add sfp-bus to
bridge between network devices and sfp cages") where additional function
were added after phylink_parse_fixedlink() making the release of link_gpio
needed if such additional function errored out.

While at it, restructure the exit condition of phylink_create() with the
goto pattern to reduce code duplication on handling error conditions.

Fixes: ce0aa27ff3f6 ("sfp: add sfp-bus to bridge between network devices and sfp cages")
Signed-off-by: Christian Marangi &lt;ansuelsmth@gmail.com&gt;
Reviewed-by: Andrew Lunn &lt;andrew@lunn.ch&gt;
Link: https://patch.msgid.link/20260726150806.2437-1-ansuelsmth@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
In phylink_create() if phylink_register_sfp() returns an error, link_gpio
obtained by phylink_parse_fixedlink() is never released. While this is a
very unlikely scenario, it's worth to fix/handle this.

This was present from the very first implementation of phylink but got
relevant only with the introduction of ce0aa27ff3f6 ("sfp: add sfp-bus to
bridge between network devices and sfp cages") where additional function
were added after phylink_parse_fixedlink() making the release of link_gpio
needed if such additional function errored out.

While at it, restructure the exit condition of phylink_create() with the
goto pattern to reduce code duplication on handling error conditions.

Fixes: ce0aa27ff3f6 ("sfp: add sfp-bus to bridge between network devices and sfp cages")
Signed-off-by: Christian Marangi &lt;ansuelsmth@gmail.com&gt;
Reviewed-by: Andrew Lunn &lt;andrew@lunn.ch&gt;
Link: https://patch.msgid.link/20260726150806.2437-1-ansuelsmth@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: phy: marvell: fix return code</title>
<updated>2026-07-21T00:51:46+00:00</updated>
<author>
<name>Michael Walle</name>
<email>mwalle@kernel.org</email>
</author>
<published>2026-07-06T12:06:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=7d8ca62d6a9ef593780161586b4efc811ac094fe'/>
<id>7d8ca62d6a9ef593780161586b4efc811ac094fe</id>
<content type='text'>
Return the correct error code, not the value written to the register.

Fixes: a219912e0fec ("net: phy: marvell: implement config_inband() method")
Signed-off-by: Michael Walle &lt;mwalle@kernel.org&gt;
Reviewed-by: Maxime Chevallier &lt;maxime.chevallier@bootlin.com&gt;
Link: https://patch.msgid.link/20260706120637.1947685-1-mwalle@kernel.org
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Return the correct error code, not the value written to the register.

Fixes: a219912e0fec ("net: phy: marvell: implement config_inband() method")
Signed-off-by: Michael Walle &lt;mwalle@kernel.org&gt;
Reviewed-by: Maxime Chevallier &lt;maxime.chevallier@bootlin.com&gt;
Link: https://patch.msgid.link/20260706120637.1947685-1-mwalle@kernel.org
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Revert "net: phy: sfp: probe for RollBall I2C-to-MDIO bridge in mdio-i2c"</title>
<updated>2026-06-30T02:07:42+00:00</updated>
<author>
<name>Petr Wozniak</name>
<email>petr.wozniak@gmail.com</email>
</author>
<published>2026-06-27T17:32:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b521003c27ebf29701ead5baf217462425c584aa'/>
<id>b521003c27ebf29701ead5baf217462425c584aa</id>
<content type='text'>
This reverts commit 8fe125892f40 ("net: phy: sfp: probe for RollBall
I2C-to-MDIO bridge in mdio-i2c").

That commit added a RollBall bridge probe at MDIO bus creation time, in
i2c_mii_init_rollball(), to avoid a multi-minute PHY probe retry loop on
modules without a bridge (e.g. RTL8261BE). The probe runs in SFP_S_INIT,
before genuine RollBall modules have finished their firmware/bridge
initialization, so the bridge does not yet answer CMD_READ/CMD_DONE. The
probe times out, mdio_protocol is set to MDIO_I2C_NONE, and PHY detection
is then skipped for genuine RollBall modules that worked before the commit.

This was confirmed on hardware by Maxime Chevallier and Aleksander
Bajkowski: their RollBall modules no longer detect a PHY, and work again
on v7.0 (before the bridge probing was introduced). The Sashiko static
review flagged the same path.

Deferring the probe to PHY discovery time does not fix it either: at that
point a slow module may still be initializing, so the probe still returns
-ENODEV. A proper fix needs per-module init timing (a longer module_t_wait
or a per-module quirk, per SFF-8472 the host must also wait at least 300 ms
after insertion), which requires genuine RollBall hardware to develop and
validate. Revert to restore the previous, working behaviour in the meantime.

The RTL8261BE retry-loop latency that the reverted commit addressed is
handled in our downstream tree, so reverting upstream is safe on our side.

Fixes: 8fe125892f40 ("net: phy: sfp: probe for RollBall I2C-to-MDIO bridge in mdio-i2c")
Reported-by: Aleksander Bajkowski &lt;olek2@wp.pl&gt;
Suggested-by: Maxime Chevallier &lt;maxime.chevallier@bootlin.com&gt;
Link: https://lore.kernel.org/netdev/20260624084814.20972-1-petr.wozniak@gmail.com/
Signed-off-by: Petr Wozniak &lt;petr.wozniak@gmail.com&gt;
Tested-by: Maxime Chevallier &lt;maxime.chevallier@bootlin.com&gt;
Reviewed-by: Maxime Chevallier &lt;maxime.chevallier@bootlin.com&gt;
Link: https://patch.msgid.link/23e3931915c3ed2a14cec95f1490e43d30b225e8.1782581445.git.petr.wozniak@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This reverts commit 8fe125892f40 ("net: phy: sfp: probe for RollBall
I2C-to-MDIO bridge in mdio-i2c").

That commit added a RollBall bridge probe at MDIO bus creation time, in
i2c_mii_init_rollball(), to avoid a multi-minute PHY probe retry loop on
modules without a bridge (e.g. RTL8261BE). The probe runs in SFP_S_INIT,
before genuine RollBall modules have finished their firmware/bridge
initialization, so the bridge does not yet answer CMD_READ/CMD_DONE. The
probe times out, mdio_protocol is set to MDIO_I2C_NONE, and PHY detection
is then skipped for genuine RollBall modules that worked before the commit.

This was confirmed on hardware by Maxime Chevallier and Aleksander
Bajkowski: their RollBall modules no longer detect a PHY, and work again
on v7.0 (before the bridge probing was introduced). The Sashiko static
review flagged the same path.

Deferring the probe to PHY discovery time does not fix it either: at that
point a slow module may still be initializing, so the probe still returns
-ENODEV. A proper fix needs per-module init timing (a longer module_t_wait
or a per-module quirk, per SFF-8472 the host must also wait at least 300 ms
after insertion), which requires genuine RollBall hardware to develop and
validate. Revert to restore the previous, working behaviour in the meantime.

The RTL8261BE retry-loop latency that the reverted commit addressed is
handled in our downstream tree, so reverting upstream is safe on our side.

Fixes: 8fe125892f40 ("net: phy: sfp: probe for RollBall I2C-to-MDIO bridge in mdio-i2c")
Reported-by: Aleksander Bajkowski &lt;olek2@wp.pl&gt;
Suggested-by: Maxime Chevallier &lt;maxime.chevallier@bootlin.com&gt;
Link: https://lore.kernel.org/netdev/20260624084814.20972-1-petr.wozniak@gmail.com/
Signed-off-by: Petr Wozniak &lt;petr.wozniak@gmail.com&gt;
Tested-by: Maxime Chevallier &lt;maxime.chevallier@bootlin.com&gt;
Reviewed-by: Maxime Chevallier &lt;maxime.chevallier@bootlin.com&gt;
Link: https://patch.msgid.link/23e3931915c3ed2a14cec95f1490e43d30b225e8.1782581445.git.petr.wozniak@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: phy: sfp: free mii_bus in sfp_i2c_mdiobus_destroy</title>
<updated>2026-06-30T02:07:42+00:00</updated>
<author>
<name>Petr Wozniak</name>
<email>petr.wozniak@gmail.com</email>
</author>
<published>2026-06-27T17:32:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=8f31efff9206f9f0adb853cad6916086aac4d5ef'/>
<id>8f31efff9206f9f0adb853cad6916086aac4d5ef</id>
<content type='text'>
sfp_i2c_mdiobus_create() allocates the I2C MDIO bus with mdio_i2c_alloc(),
a plain (non-devm) allocation, and registers it. sfp_i2c_mdiobus_destroy()
only unregisters the bus and clears sfp-&gt;i2c_mii without calling
mdiobus_free(). As the only reference to the bus is then cleared, the
struct mii_bus is leaked.

This is hit whenever a copper/RollBall SFP module that instantiated an MDIO
bus is removed: sfp_sm_main() takes the global teardown path and calls
sfp_i2c_mdiobus_destroy(). sfp_cleanup(), on driver unbind, frees
sfp-&gt;i2c_mii directly, which is why the leak only triggered on module
hot-removal and not on unbind.

Free the bus in sfp_i2c_mdiobus_destroy() to match the allocation done in
sfp_i2c_mdiobus_create().

Fixes: e85b1347ace6 ("net: sfp: create/destroy I2C mdiobus before PHY probe/after PHY release")
Signed-off-by: Petr Wozniak &lt;petr.wozniak@gmail.com&gt;
Reviewed-by: Maxime Chevallier &lt;maxime.chevallier@bootlin.com&gt;
Reviewed-by: Larysa Zaremba &lt;larysa.zaremba@intel.com&gt;
Link: https://patch.msgid.link/312bde8176fc429aa89524e3be250137f034ba84.1782581445.git.petr.wozniak@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
sfp_i2c_mdiobus_create() allocates the I2C MDIO bus with mdio_i2c_alloc(),
a plain (non-devm) allocation, and registers it. sfp_i2c_mdiobus_destroy()
only unregisters the bus and clears sfp-&gt;i2c_mii without calling
mdiobus_free(). As the only reference to the bus is then cleared, the
struct mii_bus is leaked.

This is hit whenever a copper/RollBall SFP module that instantiated an MDIO
bus is removed: sfp_sm_main() takes the global teardown path and calls
sfp_i2c_mdiobus_destroy(). sfp_cleanup(), on driver unbind, frees
sfp-&gt;i2c_mii directly, which is why the leak only triggered on module
hot-removal and not on unbind.

Free the bus in sfp_i2c_mdiobus_destroy() to match the allocation done in
sfp_i2c_mdiobus_create().

Fixes: e85b1347ace6 ("net: sfp: create/destroy I2C mdiobus before PHY probe/after PHY release")
Signed-off-by: Petr Wozniak &lt;petr.wozniak@gmail.com&gt;
Reviewed-by: Maxime Chevallier &lt;maxime.chevallier@bootlin.com&gt;
Reviewed-by: Larysa Zaremba &lt;larysa.zaremba@intel.com&gt;
Link: https://patch.msgid.link/312bde8176fc429aa89524e3be250137f034ba84.1782581445.git.petr.wozniak@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: phy: realtek: Clear MDIO_AN_10GBT_CTRL_ADV10G bit</title>
<updated>2026-06-25T01:41:00+00:00</updated>
<author>
<name>Jan Klos</name>
<email>honza.klos@gmail.com</email>
</author>
<published>2026-06-20T01:19:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=510a283f4d12367a3f811f382a2c89202954bbd1'/>
<id>510a283f4d12367a3f811f382a2c89202954bbd1</id>
<content type='text'>
On RTL8127A connected to a link partner that advertises 10000baseT
speed cannot be changed to anything other than 10000baseT as 10GbE
is always advertised regardless of any setting. Fix this by
clearing MDIO_AN_10GBT_CTRL_ADV10G bit in rtl822x_config_aneg()'s
call to phy_modify_mmd_changed().

Fixes: 83d962316128 ("net: phy: realtek: add RTL8127-internal PHY")
Reviewed-by: Maxime Chevallier &lt;maxime.chevallier@bootlin.com&gt;
Signed-off-by: Jan Klos &lt;honza.klos@gmail.com&gt;
Link: https://patch.msgid.link/20260620011956.37181-1-honza.klos@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
On RTL8127A connected to a link partner that advertises 10000baseT
speed cannot be changed to anything other than 10000baseT as 10GbE
is always advertised regardless of any setting. Fix this by
clearing MDIO_AN_10GBT_CTRL_ADV10G bit in rtl822x_config_aneg()'s
call to phy_modify_mmd_changed().

Fixes: 83d962316128 ("net: phy: realtek: add RTL8127-internal PHY")
Reviewed-by: Maxime Chevallier &lt;maxime.chevallier@bootlin.com&gt;
Signed-off-by: Jan Klos &lt;honza.klos@gmail.com&gt;
Link: https://patch.msgid.link/20260620011956.37181-1-honza.klos@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: sfp: extend SMBus support</title>
<updated>2026-06-15T21:14:48+00:00</updated>
<author>
<name>Jonas Jelonek</name>
<email>jelonek.jonas@gmail.com</email>
</author>
<published>2026-06-14T13:34:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=58b29bdf6186a8c3f2d725619c0b17cf602ac4e0'/>
<id>58b29bdf6186a8c3f2d725619c0b17cf602ac4e0</id>
<content type='text'>
Commit 7662abf4db94 ("net: phy: sfp: Add support for SMBus module access")
added SMBus access for SFP modules, but limited it to single-byte
transfers. As a side effect, hwmon is disabled (16-bit reads cannot be
guaranteed atomic) and a warning is printed.

Many SMBus-only I2C controllers in the wild support more than just
byte access, and SFP cages are often wired to such controllers
rather than to a full-featured I2C controller -- e.g. the SMBus
controllers in the Realtek longan and mango SoCs, which advertise
word access and I2C block reads. Today, they cannot drive an SFP at
all without falling back to the byte-only path.

Extend sfp_smbus_read()/sfp_smbus_write() so that, in addition to
the existing byte access, they also use SMBus word access and SMBus
I2C block access whenever the adapter advertises them. Both
directions are handled in a single read and a single write helper
that pick the largest supported transfer per chunk and fall back as
needed.

I2C-block is preferred unconditionally when available: the protocol
carries any length 1..32, so it can serve every chunk -- including
the 1- and 2-byte tails -- without help from word or byte access.
Note that this requires I2C_FUNC_SMBUS_I2C_BLOCK, which reads a
caller-specified number of bytes. This deviates from the official
SMBus Block Read (length is supplied by the slave) but is widely
supported by Linux I2C controllers/drivers.

Capability matrix this implementation supports:

  - BYTE only:                  works (unchanged behaviour); 1-byte
                                xfers, hwmon disabled.
  - BYTE + WORD:                word for &gt;=2-byte chunks, byte for
                                trailing odd byte.
  - I2C_BLOCK present (with or
    without BYTE/WORD):         block as the universal transport for
                                every chunk.
  - WORD only (no BYTE/BLOCK):  accepted with WARN_ONCE. Even-length
                                transfers work; odd-length transfers
                                (e.g. the 3-byte cotsworks fixup
                                write) hit the BYTE branch which the
                                adapter does not implement, so the
                                xfer returns an error and the
                                operation is aborted. No mainline
                                I2C driver was found to advertise
                                WORD without BYTE; the warning lets
                                us learn about it if it ever shows
                                up.

Adapters with asymmetric R/W capabilities (e.g. only READ_I2C_BLOCK
but not WRITE_I2C_BLOCK) remain functionally correct -- the
per-iteration fallback uses the direction-specific bits -- but the
shared i2c_max_block_size is sized by the all-bits-set check, so a
transfer in the better-supported direction is not upgraded. None of
the mainline I2C bus drivers surveyed during review advertise such
asymmetry; promoting i2c_max_block_size to per-direction sizes can
be revisited if needed.

Signed-off-by: Jonas Jelonek &lt;jelonek.jonas@gmail.com&gt;
Reviewed-by: Maxime Chevallier &lt;maxime.chevallier@bootlin.com&gt;
Link: https://patch.msgid.link/20260614133418.2068201-3-jelonek.jonas@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Commit 7662abf4db94 ("net: phy: sfp: Add support for SMBus module access")
added SMBus access for SFP modules, but limited it to single-byte
transfers. As a side effect, hwmon is disabled (16-bit reads cannot be
guaranteed atomic) and a warning is printed.

Many SMBus-only I2C controllers in the wild support more than just
byte access, and SFP cages are often wired to such controllers
rather than to a full-featured I2C controller -- e.g. the SMBus
controllers in the Realtek longan and mango SoCs, which advertise
word access and I2C block reads. Today, they cannot drive an SFP at
all without falling back to the byte-only path.

Extend sfp_smbus_read()/sfp_smbus_write() so that, in addition to
the existing byte access, they also use SMBus word access and SMBus
I2C block access whenever the adapter advertises them. Both
directions are handled in a single read and a single write helper
that pick the largest supported transfer per chunk and fall back as
needed.

I2C-block is preferred unconditionally when available: the protocol
carries any length 1..32, so it can serve every chunk -- including
the 1- and 2-byte tails -- without help from word or byte access.
Note that this requires I2C_FUNC_SMBUS_I2C_BLOCK, which reads a
caller-specified number of bytes. This deviates from the official
SMBus Block Read (length is supplied by the slave) but is widely
supported by Linux I2C controllers/drivers.

Capability matrix this implementation supports:

  - BYTE only:                  works (unchanged behaviour); 1-byte
                                xfers, hwmon disabled.
  - BYTE + WORD:                word for &gt;=2-byte chunks, byte for
                                trailing odd byte.
  - I2C_BLOCK present (with or
    without BYTE/WORD):         block as the universal transport for
                                every chunk.
  - WORD only (no BYTE/BLOCK):  accepted with WARN_ONCE. Even-length
                                transfers work; odd-length transfers
                                (e.g. the 3-byte cotsworks fixup
                                write) hit the BYTE branch which the
                                adapter does not implement, so the
                                xfer returns an error and the
                                operation is aborted. No mainline
                                I2C driver was found to advertise
                                WORD without BYTE; the warning lets
                                us learn about it if it ever shows
                                up.

Adapters with asymmetric R/W capabilities (e.g. only READ_I2C_BLOCK
but not WRITE_I2C_BLOCK) remain functionally correct -- the
per-iteration fallback uses the direction-specific bits -- but the
shared i2c_max_block_size is sized by the all-bits-set check, so a
transfer in the better-supported direction is not upgraded. None of
the mainline I2C bus drivers surveyed during review advertise such
asymmetry; promoting i2c_max_block_size to per-direction sizes can
be revisited if needed.

Signed-off-by: Jonas Jelonek &lt;jelonek.jonas@gmail.com&gt;
Reviewed-by: Maxime Chevallier &lt;maxime.chevallier@bootlin.com&gt;
Link: https://patch.msgid.link/20260614133418.2068201-3-jelonek.jonas@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: sfp: apply I2C adapter quirks to limit block size</title>
<updated>2026-06-15T21:14:48+00:00</updated>
<author>
<name>Jonas Jelonek</name>
<email>jelonek.jonas@gmail.com</email>
</author>
<published>2026-06-14T13:34:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f2a138abfb719a3bfd370ca79f00055ec81e4f59'/>
<id>f2a138abfb719a3bfd370ca79f00055ec81e4f59</id>
<content type='text'>
The SFP driver assumes all I2C adapters support reading and writing the
pre-defined block size SFP_EEPROM_BLOCK_SIZE of 16 bytes. This constant
was probably chosen based on good guesses and known limitations of a
range of I2C adapters and SFP modules.

However, I2C adapters may even support less and usually need to specify
this via I2C quirks. Theoretically, such an adapter may provide full
functionality but only support a read and write length of e.g. 8 bytes.
Currently, the SFP driver doesn't account for that.

Add handling for I2C quirks in SFP I2C configuration taking the fields
max_read_len and max_write_len in struct i2c_adapter_quirks into account
to further limit the maximum block size if needed.

Signed-off-by: Jonas Jelonek &lt;jelonek.jonas@gmail.com&gt;
Reviewed-by: Maxime Chevallier &lt;maxime.chevallier@bootlin.com&gt;
Link: https://patch.msgid.link/20260614133418.2068201-2-jelonek.jonas@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The SFP driver assumes all I2C adapters support reading and writing the
pre-defined block size SFP_EEPROM_BLOCK_SIZE of 16 bytes. This constant
was probably chosen based on good guesses and known limitations of a
range of I2C adapters and SFP modules.

However, I2C adapters may even support less and usually need to specify
this via I2C quirks. Theoretically, such an adapter may provide full
functionality but only support a read and write length of e.g. 8 bytes.
Currently, the SFP driver doesn't account for that.

Add handling for I2C quirks in SFP I2C configuration taking the fields
max_read_len and max_write_len in struct i2c_adapter_quirks into account
to further limit the maximum block size if needed.

Signed-off-by: Jonas Jelonek &lt;jelonek.jonas@gmail.com&gt;
Reviewed-by: Maxime Chevallier &lt;maxime.chevallier@bootlin.com&gt;
Link: https://patch.msgid.link/20260614133418.2068201-2-jelonek.jonas@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
