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Some integrated ATI Radeon chipset implementations with add-on HDMI card
(e. g. Asus M2A-VM HDMI) indicate the availability of a DDC even
when the add-on card is not plugged in or HDMI is disabled in BIOS setup.
In this case, drm_get_edid() and drm_edid_block_valid() periodically
dump data and kernel errors into system log files and onto terminals.
For these connectors DDC probing is extended by a check for a correct
EDID header. Only in case a valid EDID header is also found, the
(HDMI or DVI) connector will be used by the Radeon driver. This prevents
the kernel driver from useless flooding of logs and terminal sessions with
EDID dumps and error messages.
This patch adds a flag 'requires_extended_probe' to the radeon_connector
structure. In function radeon_connector_needs_extended_probe() this flag
can be set on a chipset family/vendor/connector type specific basis.
In addition, function radeon_ddc_probe() has been adapted to perform
extended DDC probing if required by the connector's flag.
Requires function drm_edid_header_is_valid() in DRM module provided by
[PATCH] drm: Separate EDID Header Check from EDID Block Check.
Tested for kernel 2.6.35, 2.6.38 and 3.0 on Asus M2A-VM HDMI board
BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=668196
BugLink: http://bugs.launchpad.net/bugs/7228066
Cc: <stable@kernel.org>
Signed-off-by: Thomas Reim <reimth@gmail.com>
Reviewed-by: Alex Deucher <alexdeucher@gmail.com>
Acked-by: Stephen Michaels <Stephen.Micheals@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
************************************************************
* For the very latest on DRI development, please see: *
* http://dri.freedesktop.org/ *
************************************************************
The Direct Rendering Manager (drm) is a device-independent kernel-level
device driver that provides support for the XFree86 Direct Rendering
Infrastructure (DRI).
The DRM supports the Direct Rendering Infrastructure (DRI) in four major
ways:
1. The DRM provides synchronized access to the graphics hardware via
the use of an optimized two-tiered lock.
2. The DRM enforces the DRI security policy for access to the graphics
hardware by only allowing authenticated X11 clients access to
restricted regions of memory.
3. The DRM provides a generic DMA engine, complete with multiple
queues and the ability to detect the need for an OpenGL context
switch.
4. The DRM is extensible via the use of small device-specific modules
that rely extensively on the API exported by the DRM module.
Documentation on the DRI is available from:
http://dri.freedesktop.org/wiki/Documentation
http://sourceforge.net/project/showfiles.php?group_id=387
http://dri.sourceforge.net/doc/
For specific information about kernel-level support, see:
The Direct Rendering Manager, Kernel Support for the Direct Rendering
Infrastructure
http://dri.sourceforge.net/doc/drm_low_level.html
Hardware Locking for the Direct Rendering Infrastructure
http://dri.sourceforge.net/doc/hardware_locking_low_level.html
A Security Analysis of the Direct Rendering Infrastructure
http://dri.sourceforge.net/doc/security_low_level.html