Dear Carsten,

Am Donnerstag, den 15.03.2012, 00:35 +0100 schrieb Carsten Emde:

Einfaches Textdokument-Anlage (drivers-gpu-drm-allow-to-load-edid-firmware.patch)

somehow your message was send as an attachment. Could you configure your mailer (quilt) that it is send inline?

Broken monitors and/or broken graphic boards may send erroneous or no EDID data. This also applies to broken KVM devices that are unable to correctly forward the EDID data of the connected monitor but invent their own fantasy data.

This patch allows to specify an EDID data set to be used instead of probing the monitor for it. It contains built-in data sets of frequently used screen resolutions. In addition, a particular EDID data set may be provided in the /lib/firmware directory and loaded via the firmware interface. The name is passed to the kernel as module parameter of the drm_kms_helper module either when loaded options drm_kms_helper edid_firmware=edid/1280x1024.bin or as kernel commandline parameter drm_kms_helper.edid_firmware=edid/1280x1024.bin

The built-in data sets are Resolution Name

---

1024x768 edid/1024x768.bin 1280x1024 edid/1280x1024.bin 1680x1050 edid/1680x1050.bin 1920x1080 edid/1920x1080.bin

They are ignored, if a file with the same name is available in the /lib/firmware directory.

The built-in EDID data sets are based on standard timings that may not apply to a particular monitor and even crash it. Ideally, EDID data of the connected monitor should be used. They may be obtained through the drm/cardX/cardX-<connector>/edid entry in the /sys/devices PCI directory of a correctly working graphics adapter.

It is also possible to specify the name of an EDID data set on-the-fly via the /sys/module interface, e.g. echo edid/myedid.bin >/sys/module/drm_kms_helper/parameters/edid_firmware The new screen mode is considered when the related kernel function is called for the first time after the change. Such calls are made when the X server is started or when the display settings dialog is opened in an already running X server.

Signed-off-by: Carsten Emde C.Emde@osadl.org

---

Documentation/EDID/1024x768.S | 44 ++++++ Documentation/EDID/1280x1024.S | 44 ++++++ Documentation/EDID/1680x1050.S | 44 ++++++ Documentation/EDID/1920x1080.S | 44 ++++++ Documentation/EDID/HOWTO.txt | 39 +++++ Documentation/EDID/Makefile | 25 +++ Documentation/EDID/edid.S | 261 ++++++++++++++++++++++++++++++++++++ Documentation/EDID/hex | 1 Documentation/kernel-parameters.txt | 10 + drivers/gpu/drm/Kconfig | 11 + drivers/gpu/drm/Makefile | 3 drivers/gpu/drm/drm_crtc_helper.c | 8 - drivers/gpu/drm/drm_edid.c | 4 drivers/gpu/drm/drm_edid_load.c | 241 +++++++++++++++++++++++++++++++++ include/drm/drm_crtc.h | 1 include/drm/drm_edid.h | 1 16 files changed, 778 insertions(+), 3 deletions(-)

[…]

Index: linux-3.3-rc6/Documentation/kernel-parameters.txt

--- linux-3.3-rc6.orig/Documentation/kernel-parameters.txt +++ linux-3.3-rc6/Documentation/kernel-parameters.txt @@ -713,6 +713,16 @@ bytes respectively. Such letter suffixes The filter can be disabled or changed to another driver later using sysfs.

• drm_kms_helper.edid_firmware=<file>

• 	Broken monitors, graphic adapters and KVMs may
  

• 	send no or broken EDID data sets. This parameter
  

• 	allows to specify an EDID data set in the
  

• 	/lib/firmware directory that is used instead.
  

• 	Generic built-in EDID data sets are used, if one of
  

• 	edid/1024x768.bin, edid/1280x1024.bin,
  

• 	edid/1680x1050.bin, or edid/1920x1080.bin is given
  

• 	and no file with the same name exists.
  

Maybe a hint to look into `Documentation/EDID` could be added?

• dscc4.setup= [NET]

  earlycon= [KNL] Output early console device and options.

Index: linux-3.3-rc6/drivers/gpu/drm/Kconfig

--- linux-3.3-rc6.orig/drivers/gpu/drm/Kconfig +++ linux-3.3-rc6/drivers/gpu/drm/Kconfig @@ -27,6 +27,17 @@ config DRM_KMS_HELPER help FB and CRTC helpers for KMS drivers.

+config DRM_LOAD_EDID_FIRMWARE

• bool "Allow to specify an EDID data set instead of probing for it"
• depends on DRM_KMS_HELPER
• help

•  Say Y here, if you want to use EDID data to be loaded from the
  

•  /lib/firmware directory or one of the provided built-in
  

•  data sets. This may be necessary, if the graphics adapter or
  

•  monitor are unable to provide appropriate EDID data. Since this
  

•  feature is provided as a workaround for broken hardware, the
  

•  default case is N.
  

Dito.

config DRM_TTM tristate depends on DRM

[…]

Thanks,

Paul