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commit 778c902640530371a169ad1c03566e7c51b09874 upstream In current vblank-wait implementation, if we turn off VGA output, drm_wait_vblank will still wait on the disabled pipe until timeout, because vblank on the pipe is assumed be enabled. This would cause slow system response on some system such as moblin. This patch resolve the issue by adding a drm helper function drm_vblank_off which explicitly clear vblank_enabled[crtc], wake up any waiting queue and save last vblank counter before turning off crtc. It also slightly change drm_vblank_get to ensure that we will will return immediately if trying to wait on a disabled pipe. Signed-off-by: Li Peng <peng.li@intel.com> Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org> [anholt: hand-applied for conflicts with overlay changes] Signed-off-by: Eric Anholt <eric@anholt.net> Cc: Stefan Bader <stefan.bader@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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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