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40a518d9f1
When mode setting is first initialized, the driver will call into drm_helper_initial_config() to set up an initial output and framebuffer configuration. This routine is responsible for probing the available connectors, encoders, and crtcs, looking for modes and putting together something reasonable (where reasonable is defined as "allows kernel messages to be visible on as many displays as possible"). However, the code was a bit too aggressive in setting default modes when none were found on a given connector. Even if some connectors had modes, any connectors found lacking modes would have the default 800x600 mode added to their mode list, which in some cases could cause problems later down the line. In my case, the LVDS was perfectly available, but the initial config code added 800x600 modes to both of the detected but unavailable HDMI connectors (which are on my non-existent docking station). This ended up preventing later code from setting a mode on my LVDS, which is bad. This patch fixes that behavior by making the initial config code walk through the connectors first, counting the available modes, before it decides to add any default modes to a possibly connected output. It also fixes the logic in drm_target_preferred() that was causing zeroed out modes to be set as the preferred mode for a given connector, even if no modes were available. Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org> Signed-off-by: Eric Anholt <eric@anholt.net> Signed-off-by: Dave Airlie <airlied@linux.ie>
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* For the very latest on DRI development, please see: *
* http://dri.freedesktop.org/ *
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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