linux/drivers/gpu/drm
Chris Wilson 5d031e5b63 drm/i915: Remove use of the autoreported ringbuffer HEAD position
This is a revert of 6aa56062ea.

This was originally introduced to workaround reads of the ringbuffer
registers returning 0 on SandyBridge causing hangs due to ringbuffer
overflow. The root cause here was reads through the GT powerwell require
the forcewake dance, something we only learnt of later. Now it appears
that reading the reported head position from the HWS is returning
garbage, leading once again to hangs.

For example, on q35 the autoreported head reports:
  [  217.975608] head now 00010000, actual 00010000
  [  436.725613] head now 00200000, actual 00200000
  [  462.956033] head now 00210000, actual 00210010
  [  485.501409] head now 00400000, actual 00400020
  [  508.064280] head now 00410000, actual 00410000
  [  530.576078] head now 00600000, actual 00600020
  [  553.273489] head now 00610000, actual 00610018
which appears reasonably sane. In contrast, if we look at snb:
  [  141.970680] head now 00e10000, actual 00008238
  [  141.974062] head now 02734000, actual 000083c8
  [  141.974425] head now 00e10000, actual 00008488
  [  141.980374] head now 032b5000, actual 000088b8
  [  141.980885] head now 03271000, actual 00008950
  [  142.040628] head now 02101000, actual 00008b40
  [  142.180173] head now 02734000, actual 00009050
  [  142.181090] head now 00000000, actual 00000ae0
  [  142.183737] head now 02734000, actual 00009050

In addition, the automatic reporting of the head position is scheduled
to be defeatured in the future. It has no more utility, remove it.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=45492
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Tested-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2012-02-27 08:49:56 -08:00
..
exynos drm/exynos: added postclose to release resource. 2012-02-16 09:40:54 +00:00
gma500 gma500: Fix suspend/resume functions 2012-01-27 11:52:07 +00:00
i2c gpu: add module.h to drivers/gpu files as required. 2011-10-31 19:32:03 -04:00
i810 Revert "drm/i810: cleanup reclaim_buffers" 2012-01-30 09:31:25 +00:00
i915 drm/i915: Remove use of the autoreported ringbuffer HEAD position 2012-02-27 08:49:56 -08:00
mga drm: Make the per-driver file_operations struct const 2011-11-11 11:14:47 +00:00
nouveau drm/nv50/pm: signedness bug in nv50_pm_clocks_pre() 2012-02-01 15:27:43 +10:00
r128 drm: Make the per-driver file_operations struct const 2011-11-11 11:14:47 +00:00
radeon drm/radeon/kms/atom: dpms bios scratch reg updates 2012-02-22 10:30:06 +00:00
savage drm: Make the per-driver file_operations struct const 2011-11-11 11:14:47 +00:00
sis gpu, drm, sis: Don't return uninitialized variable from sis_driver_load() 2012-01-23 11:00:47 +00:00
tdfx drm: Make the per-driver file_operations struct const 2011-11-11 11:14:47 +00:00
ttm drm/ttm: fix two regressions since move_notify changes 2012-01-25 18:54:28 +00:00
via drm/sis|via: don't return stack garbage from free_mem ioctl 2012-01-09 12:11:39 +00:00
vmwgfx vmwgfx: Fix assignment in vmw_framebuffer_create_handle 2012-01-30 09:32:39 +00:00
ati_pcigart.c gpu: Add export.h as required to drivers/gpu files. 2011-10-31 19:32:03 -04:00
drm_agpsupport.c
drm_auth.c drm: Fix authentication kernel crash 2012-01-25 09:27:45 +00:00
drm_buffer.c gpu: Add export.h as required to drivers/gpu files. 2011-10-31 19:32:03 -04:00
drm_bufs.c gpu: Add export.h as required to drivers/gpu files. 2011-10-31 19:32:03 -04:00
drm_cache.c gpu: Add export.h as required to drivers/gpu files. 2011-10-31 19:32:03 -04:00
drm_context.c drm: make DRM_UNLOCKED ioctls with their own mutex 2012-01-05 14:43:02 +00:00
drm_crtc_helper.c drm: Add drm_format_num_planes() utility function 2011-12-20 20:34:32 +00:00
drm_crtc.c drm: add support for private planes 2012-01-05 10:00:16 +00:00
drm_debugfs.c drm: serialize access to list of debugfs files 2011-11-11 11:05:19 +00:00
drm_dma.c gpu: Add export.h as required to drivers/gpu files. 2011-10-31 19:32:03 -04:00
drm_dp_i2c_helper.c
drm_drv.c drm: make DRM_UNLOCKED ioctls with their own mutex 2012-01-05 14:43:02 +00:00
drm_edid_modes.h drm/edid: support CEA video modes. 2011-12-19 14:53:16 +00:00
drm_edid.c Fix wrong assumptions in cea_for_each_detailed_block v2 2011-12-20 09:51:10 +00:00
drm_encoder_slave.c gpu: add module.h to drivers/gpu files as required. 2011-10-31 19:32:03 -04:00
drm_fb_helper.c drm: avoid switching to text console if there is no panic timeout 2011-11-10 21:27:34 +00:00
drm_fops.c drm: Fix authentication kernel crash 2012-01-25 09:27:45 +00:00
drm_gem.c drm: Pass the real error code back during GEM bo initialisation 2012-01-30 09:31:42 +00:00
drm_global.c
drm_hashtab.c gpu: Add export.h as required to drivers/gpu files. 2011-10-31 19:32:03 -04:00
drm_info.c
drm_ioc32.c drivers/gpu/drm/drm_ioc32.c: initialize all fields 2012-02-03 09:47:32 +00:00
drm_ioctl.c drm: make DRM_UNLOCKED ioctls with their own mutex 2012-01-05 14:43:02 +00:00
drm_irq.c drm: Remove utterly bogus preempt_disable() sections 2011-11-14 09:28:50 +00:00
drm_lock.c drm: add missing exports for i810 driver. 2011-12-22 19:09:01 +00:00
drm_memory.c gpu: Add export.h as required to drivers/gpu files. 2011-10-31 19:32:03 -04:00
drm_mm.c gpu: Add export.h as required to drivers/gpu files. 2011-10-31 19:32:03 -04:00
drm_modes.c gpu: Add export.h as required to drivers/gpu files. 2011-10-31 19:32:03 -04:00
drm_pci.c gpu: Add export.h as required to drivers/gpu files. 2011-10-31 19:32:03 -04:00
drm_platform.c gpu: Add export.h as required to drivers/gpu files. 2011-10-31 19:32:03 -04:00
drm_proc.c gpu: Add export.h as required to drivers/gpu files. 2011-10-31 19:32:03 -04:00
drm_scatter.c drivers: use kzalloc/kcalloc instead of 'kmalloc+memset', where possible 2011-07-25 20:57:13 -07:00
drm_stub.c
drm_sysfs.c switch device_get_devnode() and ->devnode() to umode_t * 2012-01-03 22:54:55 -05:00
drm_trace_points.c
drm_trace.h
drm_usb.c gpu: Add export.h as required to drivers/gpu files. 2011-10-31 19:32:03 -04:00
drm_vm.c gpu: Add export.h as required to drivers/gpu files. 2011-10-31 19:32:03 -04:00
Kconfig Merge tag 'v3.2-rc6' of /home/airlied/devel/kernel/linux-2.6 into drm-core-next 2011-12-20 14:43:53 +00:00
Makefile drm: kill drm_sman 2011-12-22 00:33:23 +01:00
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