linux-stable.git/drivers/usb/host, branch linux-6.5.y Linux kernel stable tree xhci: Enable RPM on controllers that support low-power states 2023-11-28T17:15:10+00:00 Basavaraj Natikar Basavaraj.Natikar@amd.com 2023-10-19T10:29:20+00:00 45fa91b09bdb247e8d9ed9831576a9d00ee0d855 commit a5d6264b638efeca35eff72177fd28d149e0764b upstream. Use the low-power states of the underlying platform to enable runtime PM. If the platform doesn't support runtime D3, then enabling default RPM will result in the controller malfunctioning, as in the case of hotplug devices not being detected because of a failed interrupt generation. Cc: Mario Limonciello <mario.limonciello@amd.com> Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20231019102924.2797346-16-mathias.nyman@linux.intel.com Cc: Oleksandr Natalenko <oleksandr@natalenko.name> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit a5d6264b638efeca35eff72177fd28d149e0764b upstream.

Use the low-power states of the underlying platform to enable runtime PM.
If the platform doesn't support runtime D3, then enabling default RPM will
result in the controller malfunctioning, as in the case of hotplug devices
not being detected because of a failed interrupt generation.

Cc: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20231019102924.2797346-16-mathias.nyman@linux.intel.com
Cc: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usb: host: xhci: Avoid XHCI resume delay if SSUSB device is not present 2023-11-28T17:14:50+00:00 Wesley Cheng quic_wcheng@quicinc.com 2023-10-19T10:29:24+00:00 95d3f58e1d4e5368679e8e5e294929c91705e748 [ Upstream commit 6add6dd345cb754ce18ff992c7264cabf31e59f6 ] There is a 120ms delay implemented for allowing the XHCI host controller to detect a U3 wakeup pulse. The intention is to wait for the device to retry the wakeup event if the USB3 PORTSC doesn't reflect the RESUME link status by the time it is checked. As per the USB3 specification: tU3WakeupRetryDelay ("Table 7-12. LTSSM State Transition Timeouts") This would allow the XHCI resume sequence to determine if the root hub needs to be also resumed. However, in case there is no device connected, or if there is only a HSUSB device connected, this delay would still affect the overall resume timing. Since this delay is solely for detecting U3 wake events (USB3 specific) then ignore this delay for the disconnected case and the HSUSB connected only case. [skip helper function, rename usb3_connected variable -Mathias ] Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20231019102924.2797346-20-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 6add6dd345cb754ce18ff992c7264cabf31e59f6 ]

There is a 120ms delay implemented for allowing the XHCI host controller to
detect a U3 wakeup pulse.  The intention is to wait for the device to retry
the wakeup event if the USB3 PORTSC doesn't reflect the RESUME link status
by the time it is checked.  As per the USB3 specification:

  tU3WakeupRetryDelay ("Table 7-12. LTSSM State Transition Timeouts")

This would allow the XHCI resume sequence to determine if the root hub
needs to be also resumed.  However, in case there is no device connected,
or if there is only a HSUSB device connected, this delay would still affect
the overall resume timing.

Since this delay is solely for detecting U3 wake events (USB3 specific)
then ignore this delay for the disconnected case and the HSUSB connected
only case.

[skip helper function, rename usb3_connected variable -Mathias ]

Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20231019102924.2797346-20-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
usb: host: xhci-plat: fix possible kernel oops while resuming 2023-11-20T10:57:17+00:00 Sergey Shtylyov s.shtylyov@omp.ru 2023-10-19T10:29:23+00:00 a43bdc6ba3427c4666b172264865cbfdee19d556 [ Upstream commit a5f928db59519a15e82ecba4ae3e7cbf5a44715a ] If this driver enables the xHC clocks while resuming from sleep, it calls clk_prepare_enable() without checking for errors and blithely goes on to read/write the xHC's registers -- which, with the xHC not being clocked, at least on ARM32 usually causes an imprecise external abort exceptions which cause kernel oops. Currently, the chips for which the driver does the clock dance on suspend/resume seem to be the Broadcom STB SoCs, based on ARM32 CPUs, as it seems... Found by Linux Verification Center (linuxtesting.org) with the Svace static analysis tool. Fixes: 8bd954c56197 ("usb: host: xhci-plat: suspend and resume clocks") Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20231019102924.2797346-19-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit a5f928db59519a15e82ecba4ae3e7cbf5a44715a ]

If this driver enables the xHC clocks while resuming from sleep, it calls
clk_prepare_enable() without checking for errors and blithely goes on to
read/write the xHC's registers -- which, with the xHC not being clocked,
at least on ARM32 usually causes an imprecise external abort exceptions
which cause kernel oops.  Currently, the chips for which the driver does
the clock dance on suspend/resume seem to be the Broadcom STB SoCs, based
on ARM32 CPUs, as it seems...

Found by Linux Verification Center (linuxtesting.org) with the Svace static
analysis tool.

Fixes: 8bd954c56197 ("usb: host: xhci-plat: suspend and resume clocks")
Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20231019102924.2797346-19-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
xhci: Loosen RPM as default policy to cover for AMD xHC 1.1 2023-11-20T10:57:17+00:00 Basavaraj Natikar Basavaraj.Natikar@amd.com 2023-10-19T10:29:19+00:00 7b8ae3c24efdc2a50b59f0075641d5f1e7f14b71 [ Upstream commit 4baf1218150985ee3ab0a27220456a1f027ea0ac ] The AMD USB host controller (1022:43f7) isn't going into PCI D3 by default without anything connected. This is because the policy that was introduced by commit a611bf473d1f ("xhci-pci: Set runtime PM as default policy on all xHC 1.2 or later devices") only covered 1.2 or later. The 1.1 specification also has the same requirement as the 1.2 specification for D3 support. So expand the runtime PM as default policy to all AMD 1.1 devices as well. Fixes: a611bf473d1f ("xhci-pci: Set runtime PM as default policy on all xHC 1.2 or later devices") Link: https://composter.com.ua/documents/xHCI_Specification_for_USB.pdf Co-developed-by: Mario Limonciello <mario.limonciello@amd.com> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com> Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20231019102924.2797346-15-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 4baf1218150985ee3ab0a27220456a1f027ea0ac ]

The AMD USB host controller (1022:43f7) isn't going into PCI D3 by default
without anything connected. This is because the policy that was introduced
by commit a611bf473d1f ("xhci-pci: Set runtime PM as default policy on all
xHC 1.2 or later devices") only covered 1.2 or later.

The 1.1 specification also has the same requirement as the 1.2
specification for D3 support. So expand the runtime PM as default policy
to all AMD 1.1 devices as well.

Fixes: a611bf473d1f ("xhci-pci: Set runtime PM as default policy on all xHC 1.2 or later devices")
Link: https://composter.com.ua/documents/xHCI_Specification_for_USB.pdf
Co-developed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20231019102924.2797346-15-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
xhci: Preserve RsvdP bits in ERSTBA register correctly 2023-10-19T21:11:02+00:00 Lukas Wunner lukas@wunner.de 2023-09-15T14:31:08+00:00 41d00825cbff0fcd01b100e9060c18bf046067ad commit cf97c5e0f7dda2edc15ecd96775fe6c355823784 upstream. xhci_add_interrupter() erroneously preserves only the lowest 4 bits when writing the ERSTBA register, not the lowest 6 bits. Fix it. Migrate the ERST_BASE_RSVDP macro to the modern GENMASK_ULL() syntax to avoid a u64 cast. This was previously fixed by commit 8c1cbec9db1a ("xhci: fix event ring segment table related masks and variables in header"), but immediately undone by commit b17a57f89f69 ("xhci: Refactor interrupter code for initial multi interrupter support."). Fixes: b17a57f89f69 ("xhci: Refactor interrupter code for initial multi interrupter support.") Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: stable@vger.kernel.org # v6.3+ Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20230915143108.1532163-5-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit cf97c5e0f7dda2edc15ecd96775fe6c355823784 upstream.

xhci_add_interrupter() erroneously preserves only the lowest 4 bits when
writing the ERSTBA register, not the lowest 6 bits.  Fix it.

Migrate the ERST_BASE_RSVDP macro to the modern GENMASK_ULL() syntax to
avoid a u64 cast.

This was previously fixed by commit 8c1cbec9db1a ("xhci: fix event ring
segment table related masks and variables in header"), but immediately
undone by commit b17a57f89f69 ("xhci: Refactor interrupter code for
initial multi interrupter support.").

Fixes: b17a57f89f69 ("xhci: Refactor interrupter code for initial multi interrupter support.")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: stable@vger.kernel.org # v6.3+
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20230915143108.1532163-5-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
xhci: Clear EHB bit only at end of interrupt handler 2023-10-19T21:11:02+00:00 Lukas Wunner lukas@wunner.de 2023-09-15T14:31:07+00:00 c247dfde7e401cff134f32063d591a4487faa785 commit 15f3ef070933817fac2bcbdb9c85bff9e54e9f80 upstream. The Event Handler Busy bit shall be cleared by software when the Event Ring is empty. The xHC is thereby informed that it may raise another interrupt once it has enqueued new events (sec 4.17.2). However since commit dc0ffbea5729 ("usb: host: xhci: update event ring dequeue pointer on purpose"), the EHB bit is already cleared after half a segment has been processed. As a result, spurious interrupts may occur: - xhci_irq() processes half a segment, clears EHB, continues processing remaining events. - xHC enqueues new events. Because EHB has been cleared, xHC sets Interrupt Pending bit. Interrupt moderation countdown begins. - Meanwhile xhci_irq() continues processing events. Interrupt moderation countdown reaches zero, so an MSI interrupt is signaled. - xhci_irq() empties the Event Ring, clears EHB again and is done. - Because an MSI interrupt has been signaled, xhci_irq() is run again. It discovers there's nothing to do and returns IRQ_NONE. Avoid by clearing the EHB bit only at the end of xhci_irq(). Fixes: dc0ffbea5729 ("usb: host: xhci: update event ring dequeue pointer on purpose") Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: stable@vger.kernel.org # v5.5+ Cc: Peter Chen <peter.chen@kernel.org> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20230915143108.1532163-4-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 15f3ef070933817fac2bcbdb9c85bff9e54e9f80 upstream.

The Event Handler Busy bit shall be cleared by software when the Event
Ring is empty.  The xHC is thereby informed that it may raise another
interrupt once it has enqueued new events (sec 4.17.2).

However since commit dc0ffbea5729 ("usb: host: xhci: update event ring
dequeue pointer on purpose"), the EHB bit is already cleared after half
a segment has been processed.

As a result, spurious interrupts may occur:

- xhci_irq() processes half a segment, clears EHB, continues processing
  remaining events.
- xHC enqueues new events.  Because EHB has been cleared, xHC sets
  Interrupt Pending bit.  Interrupt moderation countdown begins.
- Meanwhile xhci_irq() continues processing events.  Interrupt
  moderation countdown reaches zero, so an MSI interrupt is signaled.
- xhci_irq() empties the Event Ring, clears EHB again and is done.
- Because an MSI interrupt has been signaled, xhci_irq() is run again.
  It discovers there's nothing to do and returns IRQ_NONE.

Avoid by clearing the EHB bit only at the end of xhci_irq().

Fixes: dc0ffbea5729 ("usb: host: xhci: update event ring dequeue pointer on purpose")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: stable@vger.kernel.org # v5.5+
Cc: Peter Chen <peter.chen@kernel.org>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20230915143108.1532163-4-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
xhci: track port suspend state correctly in unsuccessful resume cases 2023-10-19T21:11:02+00:00 Mathias Nyman mathias.nyman@linux.intel.com 2023-09-15T14:31:06+00:00 c4ea3c85a64a9de54a42e0a778b5e67cad95b1e2 commit d7cdfc319b2bcf6899ab0a05eec0958bc802a9a1 upstream. xhci-hub.c tracks suspended ports in a suspended_port bitfield. This is checked when responding to a Get_Status(PORT) request to see if a port in running U0 state was recently resumed, and adds the required USB_PORT_STAT_C_SUSPEND change bit in those cases. The suspended_port bit was left uncleared if a device is disconnected during suspend. The bit remained set even when a new device was connected and enumerated. The set bit resulted in a incorrect Get_Status(PORT) response with a bogus USB_PORT_STAT_C_SUSPEND change bit set once the new device reached U0 link state. USB_PORT_STAT_C_SUSPEND change bit is only used for USB2 ports, but xhci-hub keeps track of both USB2 and USB3 suspended ports. Cc: stable@vger.kernel.org Reported-by: Wesley Cheng <quic_wcheng@quicinc.com> Closes: https://lore.kernel.org/linux-usb/d68aa806-b26a-0e43-42fb-b8067325e967@quicinc.com/ Fixes: 1d5810b6923c ("xhci: Rework port suspend structures for limited ports.") Tested-by: Wesley Cheng <quic_wcheng@quicinc.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20230915143108.1532163-3-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit d7cdfc319b2bcf6899ab0a05eec0958bc802a9a1 upstream.

xhci-hub.c tracks suspended ports in a suspended_port bitfield.
This is checked when responding to a Get_Status(PORT) request to see if a
port in running U0 state was recently resumed, and adds the required
USB_PORT_STAT_C_SUSPEND change bit in those cases.

The suspended_port bit was left uncleared if a device is disconnected
during suspend. The bit remained set even when a new device was connected
and enumerated. The set bit resulted in a incorrect Get_Status(PORT)
response with a bogus USB_PORT_STAT_C_SUSPEND change
bit set once the new device reached U0 link state.

USB_PORT_STAT_C_SUSPEND change bit is only used for USB2 ports, but
xhci-hub keeps track of both USB2 and USB3 suspended ports.

Cc: stable@vger.kernel.org
Reported-by: Wesley Cheng <quic_wcheng@quicinc.com>
Closes: https://lore.kernel.org/linux-usb/d68aa806-b26a-0e43-42fb-b8067325e967@quicinc.com/
Fixes: 1d5810b6923c ("xhci: Rework port suspend structures for limited ports.")
Tested-by: Wesley Cheng <quic_wcheng@quicinc.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20230915143108.1532163-3-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usb: xhci: xhci-ring: Use sysdev for mapping bounce buffer 2023-10-19T21:11:02+00:00 Wesley Cheng quic_wcheng@quicinc.com 2023-09-15T14:31:05+00:00 acf5731ea0dee166ed04f5b7ef8765cf5c91df27 commit 41a43013d2366db5b88b42bbcd8e8f040b6ccf21 upstream. As mentioned in: commit 474ed23a6257 ("xhci: align the last trb before link if it is easily splittable.") A bounce buffer is utilized for ensuring that transfers that span across ring segments are aligned to the EP's max packet size. However, the device that is used to map the DMA buffer to is currently using the XHCI HCD, which does not carry any DMA operations in certain configrations. Migration to using the sysdev entry was introduced for DWC3 based implementations where the IOMMU operations are present. Replace the reference to the controller device to sysdev instead. This allows the bounce buffer to be properly mapped to any implementations that have an IOMMU involved. cc: stable@vger.kernel.org Fixes: 4c39d4b949d3 ("usb: xhci: use bus->sysdev for DMA configuration") Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20230915143108.1532163-2-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 41a43013d2366db5b88b42bbcd8e8f040b6ccf21 upstream.

As mentioned in:
  commit 474ed23a6257 ("xhci: align the last trb before link if it is
easily splittable.")

A bounce buffer is utilized for ensuring that transfers that span across
ring segments are aligned to the EP's max packet size.  However, the device
that is used to map the DMA buffer to is currently using the XHCI HCD,
which does not carry any DMA operations in certain configrations.
Migration to using the sysdev entry was introduced for DWC3 based
implementations where the IOMMU operations are present.

Replace the reference to the controller device to sysdev instead.  This
allows the bounce buffer to be properly mapped to any implementations that
have an IOMMU involved.

cc: stable@vger.kernel.org
Fixes: 4c39d4b949d3 ("usb: xhci: use bus->sysdev for DMA configuration")
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20230915143108.1532163-2-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usb: ehci: add workaround for chipidea PORTSC.PEC bug 2023-09-23T09:14:29+00:00 Xu Yang xu.yang_2@nxp.com 2023-08-09T02:44:31+00:00 ba3df8cc094a086fa951586224637193afb557dc [ Upstream commit dda4b60ed70bd670eefda081f70c0cb20bbeb1fa ] Some NXP processor using chipidea IP has a bug when frame babble is detected. As per 4.15.1.1.1 Serial Bus Babble: A babble condition also exists if IN transaction is in progress at High-speed SOF2 point. This is called frame babble. The host controller must disable the port to which the frame babble is detected. The USB controller has disabled the port (PE cleared) and has asserted USBERRINT when frame babble is detected, but PEC is not asserted. Therefore, the SW isn't aware that port has been disabled. Then the SW keeps sending packets to this port, but all of the transfers will fail. This workaround will firstly assert PCD by SW when USBERRINT is detected and then judge whether port change has really occurred or not by polling roothub status. Because the PEC doesn't get asserted in our case, this patch will also assert it by SW when specific conditions are satisfied. Signed-off-by: Xu Yang <xu.yang_2@nxp.com> Acked-by: Peter Chen <peter.chen@kernel.org> Link: https://lore.kernel.org/r/20230809024432.535160-1-xu.yang_2@nxp.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit dda4b60ed70bd670eefda081f70c0cb20bbeb1fa ]

Some NXP processor using chipidea IP has a bug when frame babble is
detected.

As per 4.15.1.1.1 Serial Bus Babble:
  A babble condition also exists if IN transaction is in progress at
High-speed SOF2 point. This is called frame babble. The host controller
must disable the port to which the frame babble is detected.

The USB controller has disabled the port (PE cleared) and has asserted
USBERRINT when frame babble is detected, but PEC is not asserted.
Therefore, the SW isn't aware that port has been disabled. Then the
SW keeps sending packets to this port, but all of the transfers will
fail.

This workaround will firstly assert PCD by SW when USBERRINT is detected
and then judge whether port change has really occurred or not by polling
roothub status. Because the PEC doesn't get asserted in our case, this
patch will also assert it by SW when specific conditions are satisfied.

Signed-off-by: Xu Yang <xu.yang_2@nxp.com>
Acked-by: Peter Chen <peter.chen@kernel.org>
Link: https://lore.kernel.org/r/20230809024432.535160-1-xu.yang_2@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Revert "usb: xhci: tegra: Fix error check" 2023-07-25T15:44:10+00:00 Dan Carpenter dan.carpenter@linaro.org 2023-07-04T14:08:27+00:00 288b4fa1798e3637a9304c6e90a93d900e02369c This reverts commit 18fc7c435be3f17ea26a21b2e2312fcb9088e01f. The reverted commit was based on static analysis and a misunderstanding of how PTR_ERR() and NULLs are supposed to work. When a function returns both pointer errors and NULL then normally the NULL means "continue operating without a feature because it was deliberately turned off". The NULL should not be treated as a failure. If a driver cannot work when that feature is disabled then the KConfig should enforce that the function cannot return NULL. We should not need to test for it. In this code, the patch means that certain tegra_xusb_probe() will fail if the firmware supports power-domains but CONFIG_PM is disabled. Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org> Fixes: 18fc7c435be3 ("usb: xhci: tegra: Fix error check") Cc: stable <stable@kernel.org> Link: https://lore.kernel.org/r/8baace8d-fb4b-41a4-ad5f-848ae643a23b@moroto.mountain Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
This reverts commit 18fc7c435be3f17ea26a21b2e2312fcb9088e01f.

The reverted commit was based on static analysis and a misunderstanding
of how PTR_ERR() and NULLs are supposed to work.  When a function
returns both pointer errors and NULL then normally the NULL means
"continue operating without a feature because it was deliberately
turned off".  The NULL should not be treated as a failure.  If a driver
cannot work when that feature is disabled then the KConfig should
enforce that the function cannot return NULL.  We should not need to
test for it.

In this code, the patch means that certain tegra_xusb_probe() will
fail if the firmware supports power-domains but CONFIG_PM is disabled.

Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Fixes: 18fc7c435be3 ("usb: xhci: tegra: Fix error check")
Cc: stable <stable@kernel.org>
Link: https://lore.kernel.org/r/8baace8d-fb4b-41a4-ad5f-848ae643a23b@moroto.mountain
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>