linux/drivers/gpu/drm
Rafael J. Wysocki 8e5c2b776a Revert "ACPI / video / i915: No ACPI backlight if firmware expects Windows 8"
We attempted to address a regression introduced by commit a57f7f9
(ACPICA: Add Windows8/Server2012 string for _OSI method.) after which
ACPI video backlight support doesn't work on a number of systems,
because the relevant AML methods in the ACPI tables in their BIOSes
become useless after the BIOS has been told that the OS is compatible
with Windows 8.  That problem is tracked by the bug entry at:

https://bugzilla.kernel.org/show_bug.cgi?id=51231

Commit 8c5bd7a (ACPI / video / i915: No ACPI backlight if firmware
expects Windows 8) introduced for this purpose essentially prevented
the ACPI backlight support from being used if the BIOS had been told
that the OS was compatible with Windows 8 and the i915 driver was
loaded, in which case the backlight would always be handled by i915.
Unfortunately, however, that turned out to cause problems with
backlight to appear on multiple systems with symptoms indicating that
i915 was unable to control the backlight on those systems as
expected.

For this reason, revert commit 8c5bd7a, but leave the function
acpi_video_backlight_quirks() introduced by it, because another
commit on top of it uses that function.

References: https://lkml.org/lkml/2013/7/21/119
References: https://lkml.org/lkml/2013/7/22/261
References: https://lkml.org/lkml/2013/7/23/429
References: https://lkml.org/lkml/2013/7/23/459
References: https://lkml.org/lkml/2013/7/23/81
References: https://lkml.org/lkml/2013/7/24/27
Reported-and-tested-by: James Hogan <james@albanarts.com>
Reported-and-tested-by: Kamal Mostafa <kamal@canonical.com>
Reported-and-tested-by: Jörg Otte <jrg.otte@gmail.com>
Reported-and-tested-by: Steven Newbury <steve@snewbury.org.uk>
Reported-by: Martin Steigerwald <Martin@lichtvoll.de>
Reported-by: Kalle Valo <kvalo@adurom.com>
Tested-by: Joerg Platte <jplatte@naasa.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-07-26 14:59:20 +02:00
..
ast drm/ast: inline reservations 2013-06-28 12:04:04 +10:00
cirrus drm/cirrus: inline reservations 2013-06-28 12:04:05 +10:00
exynos drm/exynos: remove duplicated error routine and unnecessary assign 2013-07-04 15:55:37 +09:00
gma500 Merge branch 'gma500-fixes' of git://github.com/patjak/drm-gma500 into drm-fixes 2013-06-11 08:16:10 +10:00
i2c drm/i2c: nxp-tda998x (v3) 2013-02-19 17:57:44 -05:00
i810 i810: VM_IO is set by io_remap_pfn_range() 2013-06-29 12:46:40 +04:00
i915 Revert "ACPI / video / i915: No ACPI backlight if firmware expects Windows 8" 2013-07-26 14:59:20 +02:00
mga
mgag200 drm/mgag200: inline reservations 2013-06-28 12:04:06 +10:00
nouveau Merge branch 'drm-nouveau-next' of git://anongit.freedesktop.org/git/nouveau/linux-2.6 into drm-next 2013-07-09 10:48:41 +10:00
omapdrm Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux 2013-07-09 16:04:31 -07:00
qxl Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux 2013-07-09 16:04:31 -07:00
r128
radeon drm/radeon/dpm: add debugfs support for RS780/RS880 (v3) 2013-07-17 16:47:52 -04:00
rcar-du drm/rcar-du: Use the GEM PRIME helpers 2013-07-17 15:44:01 +02:00
savage drm (ast, cirrus, mgag200, nouveau, savage, vmwgfx): Remove drm_mtrr_{add, del} 2013-05-31 13:02:54 +10:00
shmobile drm/shmobile: Use the GEM PRIME helpers 2013-07-17 15:43:55 +02:00
sis drm/sis: convert to idr_alloc() 2013-02-27 19:10:16 -08:00
tdfx
tilcdc drm/tilcdc: Clear bits of register we're going to set. 2013-06-28 09:13:00 +10:00
ttm drm: make drm_mm_init() return void 2013-07-02 13:34:41 +10:00
udl drm: Drop all the stub gamma_get, gamma_set, load_lut functions from drivers 2013-06-17 19:42:47 +10:00
via drm/via: convert to idr_alloc() 2013-02-27 19:10:16 -08:00
vmwgfx drm/vmwgfx: get rid of ttm_bo_is_reserved usage 2013-06-28 12:04:14 +10:00
ati_pcigart.c
drm_agpsupport.c
drm_auth.c
drm_buffer.c
drm_bufs.c drm: Don't leak phys_wc "handles" to userspace 2013-05-31 13:37:39 +10:00
drm_cache.c lib/scatterlist: sg_page_iter: support sg lists w/o backing pages 2013-03-27 17:13:44 +01:00
drm_context.c drm: convert to idr_alloc() 2013-02-27 19:10:15 -08:00
drm_crtc_helper.c Revert "drm: kms_helper: don't lose hotplug event" 2013-06-28 20:31:34 +10:00
drm_crtc.c drm: add hotspot support for cursors. 2013-06-28 09:13:39 +10:00
drm_debugfs.c
drm_dma.c
drm_dp_helper.c
drm_drv.c drm: add hotspot support for cursors. 2013-06-28 09:13:39 +10:00
drm_edid_load.c drm: avoid warning in drm_load_edid_firmware() 2013-07-10 14:21:46 -07:00
drm_edid.c drm: add assertion for checking null edid to drm_edid_block_valid 2013-07-04 10:52:50 +10:00
drm_encoder_slave.c drm: refactor call to request_module 2013-05-10 14:46:03 +10:00
drm_fb_cma_helper.c treewide: Fix typo in printk 2013-05-28 12:02:13 +02:00
drm_fb_helper.c drm/fb-helper: Make load_lut and gamma_set/gamma_get hooks optional 2013-06-17 19:42:47 +10:00
drm_fops.c drm: fix error routines in drm_open_helper 2013-07-04 10:53:37 +10:00
drm_gem_cma_helper.c drm/cma: remove GEM CMA specific dma_buf functionality 2013-07-05 15:44:54 +10:00
drm_gem.c drm: make drm_mm_init() return void 2013-07-02 13:34:41 +10:00
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: Don't leak phys_wc "handles" to userspace 2013-05-31 13:37:39 +10:00
drm_irq.c drm: fix a use-after-free when GPU acceleration disabled 2013-06-03 19:12:04 +10:00
drm_lock.c
drm_memory.c
drm_mm.c drm/mm: WARN for unclean mm takedown 2013-07-04 10:01:12 +10:00
drm_modes.c drm: Sort connector modes based on vrefresh 2013-06-11 08:35:51 +10:00
drm_pci.c drm, agpgart: Use pgprot_writecombine for AGP maps and make the MTRR optional 2013-05-31 13:37:31 +10:00
drm_platform.c
drm_prime.c drm: add mmap function to prime helpers 2013-07-05 15:44:44 +10:00
drm_proc.c drm: proc: Use remove_proc_subtree() 2013-05-01 17:29:44 -04:00
drm_rect.c drm: Add drm_rect_debug_print() 2013-04-30 22:20:00 +02:00
drm_scatter.c
drm_stub.c drm: drm_stub: Fixing return value if driver master_set call failed 2013-06-27 21:03:16 +10:00
drm_sysfs.c drm: Convert drm class driver from legacy pm ops to dev_pm_ops 2013-07-04 10:50:26 +10:00
drm_trace_points.c
drm_trace.h drm: fix print format of sequence in trace point 2013-07-04 10:55:27 +10:00
drm_usb.c drm/usb: bind driver to correct device 2013-02-07 12:37:41 +10:00
drm_vm.c drm: io_remap_pfn_range() sets VM_IO... 2013-06-29 12:46:39 +04:00
Kconfig drm/nouveau: always select ACPI_VIDEO if ACPI is enabled. 2013-06-28 11:56:22 +10:00
Makefile drm: Renesas R-Car Display Unit DRM driver 2013-06-27 10:08:04 +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