linux/drivers/gpu/drm
Daniel Vetter b1289371fc Revert "drm/i915: write backlight harder"
This reverts commit cf0a6584aa.

Turns out that cargo-culting breaks systems. Note that we can't revert
further, since

commit 770c12312a
Author: Takashi Iwai <tiwai@suse.de>
Date:   Sat Aug 11 08:56:42 2012 +0200

    drm/i915: Fix blank panel at reopening lid

fixed a regression in 3.6-rc kernels for which we've never figured out
the exact root cause. But some further inspection of the backlight
code reveals that it's seriously lacking locking. And especially the
asle backlight update is know to get fired (through some smm magic)
when writing specific backlight control registers. So the possibility
of suffering from races is rather real.

Until those races are fixed I don't think it makes sense to try
further hacks. Which sucks a bit, but sometimes that's how it is :(

References: http://www.mail-archive.com/intel-gfx@lists.freedesktop.org/msg18788.html
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=47941
Tested-by: Takashi Iwai <tiwai@suse.de>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: stable@vger.kernel.org (the reverted commit was cc: stable, too)
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-03-24 13:23:20 +01:00
..
ast Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux 2013-02-25 16:46:44 -08:00
cirrus Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux 2013-02-25 16:46:44 -08:00
exynos drm/exynos: convert to idr_alloc() 2013-02-27 19:10:15 -08:00
gma500 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
i2c drm/i2c: nxp-tda998x (v3) 2013-02-19 17:57:44 -05:00
i810
i915 Revert "drm/i915: write backlight harder" 2013-03-24 13:23:20 +01:00
mga
mgag200 drm/mgag200: Bug fix: Modified pll algorithm for EH project 2013-03-21 10:16:58 +10:00
nouveau drm/nv50/kms: prevent lockdep false-positive in page flipping path 2013-03-19 15:26:38 +10:00
omapdrm Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
r128
radeon drm/radeon: add support for Richland APUs 2013-03-15 18:47:19 -04:00
savage
shmobile drm/shmobile: use drm_modeset_lock_all 2013-01-20 22:16:51 +01:00
sis drm/sis: convert to idr_alloc() 2013-02-27 19:10:16 -08:00
tdfx
tegra drm/tegra: drop "select DRM_HDMI" 2013-03-08 08:36:01 +10:00
tilcdc drm/tilcdc: only build on arm 2013-02-26 09:54:48 +10:00
ttm Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
udl Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
via drm/via: convert to idr_alloc() 2013-02-27 19:10:16 -08:00
vmwgfx drm/vmwgfx: convert to idr_alloc() 2013-02-27 19:10:16 -08:00
ati_pcigart.c
drm_agpsupport.c
drm_auth.c
drm_buffer.c
drm_bufs.c
drm_cache.c
drm_context.c drm: convert to idr_alloc() 2013-02-27 19:10:15 -08:00
drm_crtc_helper.c drm: don't hold crtc mutexes for connector ->detect callbacks 2013-01-20 22:17:15 +01:00
drm_crtc.c drm: convert to idr_alloc() 2013-02-27 19:10:15 -08:00
drm_debugfs.c
drm_dma.c
drm_dp_helper.c drm/doc: add new dp helpers into drm DocBook 2012-11-28 20:26:53 +10:00
drm_drv.c drm: don't use idr_remove_all() 2013-02-27 19:10:13 -08:00
drm_edid_load.c
drm_edid.c KMS: fix EDID detailed timing frame rate 2013-03-23 10:46:10 -07:00
drm_encoder_slave.c drm: i2c encoder helper wrappers 2013-02-17 17:55:42 -05:00
drm_fb_cma_helper.c Merge branch 'tilcdc-next' of git://people.freedesktop.org/~robclark/linux into drm-next 2013-02-21 09:31:47 +10:00
drm_fb_helper.c drm/fb-helper: don't sleep for screen unblank when an oopps is in progress 2013-02-14 00:08:33 +01:00
drm_fops.c drm: revamp locking around fb creation/destruction 2013-01-20 22:16:58 +01:00
drm_gem_cma_helper.c drm/cma: add debugfs helpers 2013-02-17 17:55:42 -05:00
drm_gem.c drm: convert to idr_alloc() 2013-02-27 19:10:15 -08:00
drm_global.c
drm_hashtab.c hlist: drop the node parameter from iterators 2013-02-27 19:10:24 -08:00
drm_info.c
drm_ioc32.c
drm_ioctl.c drm: add support for monotonic vblank timestamps 2012-11-20 16:06:16 +10:00
drm_irq.c drm: small fix in drm_send_vblank_event() 2013-02-17 17:55:42 -05:00
drm_lock.c
drm_memory.c
drm_mm.c Merge branch 'drm-kms-locking' of git://people.freedesktop.org/~danvet/drm-intel into drm-next 2013-01-21 07:44:58 +10:00
drm_modes.c drm_modes: add of_videomode helpers 2013-01-24 09:04:14 +01:00
drm_pci.c drm/pci: define drm_pcie_get_speed_cap_mask() only when CONFIG_PCI=y 2013-02-15 10:15:19 +10:00
drm_platform.c
drm_prime.c drm: add prime helpers 2013-02-08 13:39:08 +10:00
drm_proc.c
drm_scatter.c
drm_stub.c drm: convert to idr_alloc() 2013-02-27 19:10:15 -08:00
drm_sysfs.c drm: remove legacy drm_connector_property fxns 2012-11-30 10:30:48 -06:00
drm_trace_points.c
drm_trace.h
drm_usb.c drm/usb: bind driver to correct device 2013-02-07 12:37:41 +10:00
drm_vm.c
Kconfig drm: Add HDMI infoframe helpers 2013-02-22 08:20:10 +01:00
Makefile Merge branch 'tilcdc-next' of git://people.freedesktop.org/~robclark/linux into drm-next 2013-02-21 09:31:47 +10:00
README.drm

************************************************************
* 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