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drm/i915: Clear scanline waits after disabling the pipe.

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If we disable the pipe and the GPU is currently waiting on a scanline
WAIT_FOR_EVENT, the GPU will hang. Fortunately, there is a magic bit
which we can write on i915+ to break this wait after disabling the
pipe.

References:

  Bug 29252 - [Arrandale] Hung WAIT_FOR_EVENT when running rss-glx-skyrocket
  https://bugs.freedesktop.org/show_bug.cgi?id=29252

  Bug 28964 - [i965gm] GPU infinite MI_WAIT_FOR_EVENT while watching video in Totem
  https://bugs.freedesktop.org/show_bug.cgi?id=28964

and many others.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
This commit is contained in:
Chris Wilson 2010-08-08 11:53:53 +01:00
parent 37811fcc91
commit 4b60e5cb70
2 changed files with 31 additions and 2 deletions
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2
drivers/gpu/drm/i915/i915_reg.h
View file

@ -295,6 +295,8 @@
#define RING_VALID_MASK 0x00000001
#define RING_VALID 0x00000001
#define RING_INVALID 0x00000000
#define RING_WAIT_I8XX (1<<0) /* gen2, PRBx_HEAD */
#define RING_WAIT (1<<11) /* gen3+, PRBx_CTL */
#define PRB1_TAIL 0x02040 /* 915+ only */
#define PRB1_HEAD 0x02044 /* 915+ only */
#define PRB1_START 0x02048 /* 915+ only */

31
drivers/gpu/drm/i915/intel_display.c
View file

@ -2344,6 +2344,26 @@ static void i9xx_crtc_dpms(struct drm_crtc *crtc, int mode)
}
}
/*
* When we disable a pipe, we need to clear any pending scanline wait events
* to avoid hanging the ring, which we assume we are waiting on.
*/
static void intel_clear_scanline_wait(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
u32 tmp;
if (IS_GEN2(dev))
/* Can't break the hang on i8xx */
return;
tmp = I915_READ(PRB0_CTL);
if (tmp & RING_WAIT) {
I915_WRITE(PRB0_CTL, tmp);
POSTING_READ(PRB0_CTL);
}
}
/**
* Sets the power management mode of the pipe and plane.
*/
@ -2366,7 +2386,8 @@ static void intel_crtc_dpms(struct drm_crtc *crtc, int mode)
* with multiple pipes prior to enabling to new pipe.
*
* When switching off the display, make sure the cursor is
* properly hidden prior to disabling the pipe.
* properly hidden and there are no pending waits prior to
* disabling the pipe.
*/
if (mode == DRM_MODE_DPMS_ON)
intel_update_watermarks(dev);
@ -2377,8 +2398,14 @@ static void intel_crtc_dpms(struct drm_crtc *crtc, int mode)
if (mode == DRM_MODE_DPMS_ON)
intel_crtc_update_cursor(crtc);
else
else {
/* XXX Note that this is not a complete solution, but a hack
* to avoid the most frequently hit hang.
*/
intel_clear_scanline_wait(dev);
intel_update_watermarks(dev);
}
if (!dev->primary->master)
return;