linux/drivers/gpu/drm
Daniel Vetter 4cd53c0c8b drm/i915: paper over missed irq issues with force wake voodoo
Two things seem to do the trick on my ivb machine here:
- prevent the gt from powering down while waiting for seqno
  notification interrupts by grabbing the force_wake in get_irq (and
  dropping it in put_irq again).
- ordering writes from the ring's CS by reading a CS register, ACTHD
  seems to work.

Only the blt&bsd ring on ivb seem to be massively affected by this,
but for paranoia do this dance also on the render ring and on snb
(i.e. all gpus with forcewake).

Tested with Eric's glCopyPixels loop which without this patch scores a
missed irq every few seconds.

This patch needs my forcewake rework to use a spinlock instead of
dev->struct_mutex.

After crawling through docs a lot I've found the following nugget:

Internal doc "SNB GT PM Programming Guide", Section 4.3.1:

"GT does not generate interrupts while in RC6 (by design)"

So it looks like rc6 and irq generation are indeed related.

v2: Improve the comment per Eugeni Dodonov's suggestion.

v3: Add the documentation snipped. Also restrict the w/a to ivb only
for -fixes, as suggested by Keith Packard.

Cc: stable@kernel.org
Cc: Eric Anholt <eric@anholt.net>
Cc: Kenneth Graunke <kenneth@whitecape.org>
Cc: Eugeni Dodonov <eugeni.dodonov@intel.com>
Tested-by: Eugeni Dodonov <eugeni.dodonov@intel.com>
Reviewed-by: Eugeni Dodonov <eugeni.dodonov@intel.com>
Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Keith Packard <keithp@keithp.com>
2012-01-19 12:28:57 -08:00
..
exynos drm: add support for private planes 2012-01-05 10:00:16 +00:00
gma500 gma500: silence gcc warnings in mid_get_vbt_data() 2012-01-10 10:01:22 +00:00
i2c gpu: add module.h to drivers/gpu files as required. 2011-10-31 19:32:03 -04:00
i810 drm/i810: don't acces hw regs in lastclose 2011-12-22 19:54:58 +01:00
i915 drm/i915: paper over missed irq issues with force wake voodoo 2012-01-19 12:28:57 -08:00
mga drm: Make the per-driver file_operations struct const 2011-11-11 11:14:47 +00:00
nouveau drm/nouveau/pm: fix build with HWMON off 2012-01-10 10:13:16 +00:00
r128 drm: Make the per-driver file_operations struct const 2011-11-11 11:14:47 +00:00
radeon Merge branch 'drm-core-next' of git://people.freedesktop.org/~airlied/linux 2012-01-10 11:04:36 -08:00
savage drm: Make the per-driver file_operations struct const 2011-11-11 11:14:47 +00:00
sis drm/sis|via: don't return stack garbage from free_mem ioctl 2012-01-09 12:11:39 +00:00
tdfx drm: Make the per-driver file_operations struct const 2011-11-11 11:14:47 +00:00
ttm drm/ttm: fix condition (and vs or) 2012-01-10 10:00:42 +00:00
via drm/sis|via: don't return stack garbage from free_mem ioctl 2012-01-09 12:11:39 +00:00
vmwgfx Merge branch 'drm-core-next' of git://people.freedesktop.org/~airlied/linux 2012-01-10 11:04:36 -08:00
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_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.c drm: add support for private planes 2012-01-05 10:00:16 +00:00
drm_crtc_helper.c drm: Add drm_format_num_planes() utility function 2011-12-20 20:34:32 +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.c Fix wrong assumptions in cea_for_each_detailed_block v2 2011-12-20 09:51:10 +00:00
drm_edid_modes.h drm/edid: support CEA video modes. 2011-12-19 14:53:16 +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: Make the per-driver file_operations struct const 2011-11-11 11:14:47 +00:00
drm_gem.c drm/gem: add functions for mmap offset creation 2011-08-30 11:06:06 +01:00
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 Merge remote branch 'intel/drm-intel-next' of ../drm-next into drm-core-next 2011-03-14 14:15:13 +10:00
drm_ioc32.c gpu: Add export.h as required to drivers/gpu files. 2011-10-31 19:32:03 -04:00
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: Create and use drm_err 2011-04-28 14:53:02 +10:00
drm_sysfs.c switch device_get_devnode() and ->devnode() to umode_t * 2012-01-03 22:54:55 -05:00
drm_trace.h
drm_trace_points.c
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