linux.git/drivers/video/fb_ddc.c, branch master

video: move fbdev to drivers/video/fbdev

2014-04-17T05:10:19+00:00

The drivers/video directory is a mess. It contains generic video related
files, directories for backlight, console, linux logo, lots of fbdev
device drivers, fbdev framework files.

Make some order into the chaos by creating drivers/video/fbdev
directory, and move all fbdev related files there.

No functionality is changed, although I guess it is possible that some
subtle Makefile build order related issue could be created by this
patch.

Signed-off-by: Tomi Valkeinen 
Acked-by: Laurent Pinchart 
Acked-by: Geert Uytterhoeven 
Acked-by: Rob Clark 
Acked-by: Jingoo Han 
Acked-by: Daniel Vetter

video: Add module.h to drivers/video files who really use it.

2011-10-31T23:31:33+00:00

They were getting this implicitly by an include of module.h
from device.h -- but we are going to clean that up and break
that include chain, so include module.h explicitly now.

[ with contributions from Axel Lin  ]

Signed-off-by: Paul Gortmaker

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

2010-03-30T13:02:32+00:00

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo 
Guess-its-ok-by: Christoph Lameter 
Cc: Ingo Molnar 
Cc: Lee Schermerhorn

i2c: Let framebuffer drivers set their I2C bus class to DDC

2008-07-14T20:38:28+00:00

Let framebuffer drivers set their I2C bus class to DDC. Once this is
done, we will be able to tell the eeprom driver to only probe for
EDID EEPROMs on these buses.

Signed-off-by: Jean Delvare

fb_ddc: fix DDC lines quirk

2007-11-29T17:24:52+00:00

The code in fb_ddc_read() is said to be based on the implementation of the
radeon driver:
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=fc5891c8a3ba284f13994d7bc1f1bfa8283982de

However, comparing the old radeon driver code with the new fb_ddc code
reveals some differences.  Most notably, the I2C bus lines are held at the
end of the function, while the original code was releasing them (as the
comment above correctly says.)

There are a few other differences, which appear to be responsible for read
failures on my system.  While tracing low-level I2C code in i2c-algo-bit, I
noticed that the initial attempt to read the EDID always failed.  It takes
one retry for the read to succeed.  As we are about to remove this
automatic retry property from i2c-algo-bit, reading the EDID would really
fail.

As a summary, the I2C lines quirk which is supposedly needed to read EDID
on some older monitors is currently breaking the (first) read on all other
monitors (and might not even work with older ones - did anyone try since
October 2006?)

After applying the patch below, which makes the code in fb_ddc_read()
really similar to what the radeon driver used to have, the first EDID read
succeeds again.

On top of that, as it appears that this code has been broken for one year
now and nobody seems to have complained, I'm curious if it makes sense to
keep this quirk in place.  It makes the code more complex and slower just
for the sake of monitors which I guess nobody uses anymore.  Can't we just
get rid of it?

Signed-off-by: Jean Delvare 
Acked-by: Benjamin Herrenschmidt 
Tested-by: Roger Leigh 
Tested-by: Michael Buesch 
Cc: "Antonino A. Daplas" 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Fix generic fb_ddc i2c edid probe msg

2006-11-17T06:18:28+00:00

Benh points out that the msgs[0].flags entry never got initialized, and
since it's an automatic stack allocation, it could have any random
value, which is bad.

Rewrite the initializer to explicitly initialize all fields of the small
i2c_msg structure array we generate.  Just to keep it all obvious, let's
handle msgs[1].buf in the same initializer while we're at it, instead of
initializing that one separately later.

Signed-off-by: Linus Torvalds

[PATCH] fbdev: Add generic ddc read functionality

2006-10-03T15:04:09+00:00

Adds functionality to read the EDID information over the DDC bus in a generic
way.  This code is based on the DDC implementation in the radeon driver.

[adaplas]
- separate from fbmon.c and place in new file fb_ddc.c
- remove dependency to CONFIG_I2C and CONFIG_I2C_ALGOBIT, otherwise, feature
  will not compile if i2c support is compiled as a module
- feature is selectable only by drivers needing it. It must have a
  'select FB_DDC if xxx' in Kconfig
- change printk's to dev_*, the i2c people prefers it

Signed-off-by: Dennis Munsie 
Signed-off-by: Antonino Daplas 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds