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4 commits

Author SHA1 Message Date
Daniel Thompson
4cbe1bfa27 drm: Add 800x600 (SVGA) screen resolution to the built-in EDIDs
The 800x600 (SVGA) screen resolution was lacking in the set of
built-in selectable EDID screen resolutions that can be used to
repair misbehaving monitor firmware.

This patch adds the related data set and expands the documentation.
Note that the SVGA bit occupies a different byte to all the existing
users of the established timing bits forcing a rework of the
ESTABLISHED_TIMINGS_BITS macro.

Tested new EDID on an aged (and misbehaving) industrial LCD panel;
existing EDIDs still pass edid-decode's checksum checks.

Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: David Airlie <airlied@linux.ie>
Cc: Carsten Emde <C.Emde@osadl.org>
Cc: linux-doc@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2014-05-26 12:53:40 +10:00
Carsten Emde
8091ee5c09 drm: Add 1600x1200 (UXGA) screen resolution to the built-in EDIDs
The 1600x1200 (UXGA) screen resolution was lacking in the set of
built-in selectable EDID screen resolutions that can be used to
repair misbehaving monitor firmware.

This patch adds the related data set and expands the documentation.

Signed-off-by: Carsten Emde <C.Emde@osadl.org>
Acked-by: Paul Menzel <paulepanter@users.sourceforge.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2013-04-12 14:06:16 +10:00
Carsten Emde
bac4b7c3b5 drm: Load EDID: Explain better how to write your own EDID firmware
A description was lacking how to write an EDID firmware file that
corresponds to a given X11 setting.

Signed-off-by: Carsten Emde <C.Emde@osadl.org>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2013-01-20 19:22:19 +10:00
Carsten Emde
da0df92b57 drm: allow loading an EDID as firmware to override broken monitor
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

It is also possible to restrict the usage of a specified EDID data set
to a particular connector. This is done by prepending the name of the
connector to the name of the EDID data set using the syntax
  edid_firmware=[<connector>:]<edid>
such as, for example,
  edid_firmware=DVI-I-1:edid/1920x1080.bin
in which case no other connector will be affected.

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 even 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>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2012-03-20 10:09:28 +00:00