Attachment 68911 Details for Bug 47827 – fix overlay on i830M

[patch] fix overlay on i830M

0001-drm-i915-fix-overlay-on-i830M.patch (text/plain), 2.79 KB, created by Daniel Vetter on 2012-10-22 10:44:07 UTC

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Creator: Daniel Vetter

Created: 2012-10-22 10:44:07 UTC

Size: 2.79 KB

patch

obsolete

>From 8a3138ebad583059ffdd60f208fe5631b67303b4 Mon Sep 17 00:00:00 2001
>From: Daniel Vetter <daniel.vetter@ffwll.ch>
>Date: Mon, 22 Oct 2012 12:38:54 +0200
>Subject: [PATCH] drm/i915: fix overlay on i830M
>MIME-Version: 1.0
>Content-Type: text/plain; charset=UTF-8
>Content-Transfer-Encoding: 8bit
>
>The overlay on the i830M has a peculiar failure mode: It works the
>first time around after boot-up, but consistenly hangs the second time
>it's used.
>
>Chris Wilson has dug out a nice errata:
>
>"1.5.12 Clock Gating Disable for Display Register
>Address Offset:	06200hâ06203h
>
>"Bit 3
>Ovrunit Clock Gating Disable.
>0 = Clock gating controlled by unit enabling logic
>1 = Disable clock gating function
>DevALM Errata ALM049: Overlay Clock Gating Must be Disabled:  Overlay
>& L2 Cache clock gating must be disabled in order to prevent device
>hangs when turning off overlay.SW must turn off Ovrunit clock gating
>(6200h) and L2 Cache clock gating (C8h)."
>
>Now I've nowhere found that 0xc8 register and hence couldn't apply the
>l2 cache workaround. But I've remembered that part of the magic that
>the OVERLAY_ON/OFF commands are supposed to do is to rearrange cache
>allocations so that the overlay scaler has some scratch space.
>
>And while pondering how that could explain the hang the 2nd time we
>enable the overlay, I've remembered that the old ums overlay code did
>_not_ issue the OVERLAY_OFF cmd.
>
>And indeed, disabling the OFF cmd results in the overlay working
>flawlessly, so I guess we can workaround the lack of the above
>workaround by simply never disabling the overlay engine once it's
>enabled.
>
>Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=47827
>Cc: stable@vger.kernel.org
>Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
>---
> drivers/gpu/drm/i915/intel_overlay.c | 12 +++++++++---
> 1 file changed, 9 insertions(+), 3 deletions(-)
>
>diff --git a/drivers/gpu/drm/i915/intel_overlay.c b/drivers/gpu/drm/i915/intel_overlay.c
>index 555912f..0604af2 100644
>--- a/drivers/gpu/drm/i915/intel_overlay.c
>+++ b/drivers/gpu/drm/i915/intel_overlay.c
>@@ -342,9 +342,15 @@ static int intel_overlay_off(struct intel_overlay *overlay)
> 	intel_ring_emit(ring, flip_addr);
> 	intel_ring_emit(ring, MI_WAIT_FOR_EVENT | MI_WAIT_FOR_OVERLAY_FLIP);
> 	/* turn overlay off */
>-	intel_ring_emit(ring, MI_OVERLAY_FLIP | MI_OVERLAY_OFF);
>-	intel_ring_emit(ring, flip_addr);
>-	intel_ring_emit(ring, MI_WAIT_FOR_EVENT | MI_WAIT_FOR_OVERLAY_FLIP);
>+	if (IS_I830(dev)) {
>+		intel_ring_emit(ring, MI_NOOP);
>+		intel_ring_emit(ring, MI_NOOP);
>+		intel_ring_emit(ring, MI_NOOP);
>+	} else {
>+		intel_ring_emit(ring, MI_OVERLAY_FLIP | MI_OVERLAY_OFF);
>+		intel_ring_emit(ring, flip_addr);
>+		intel_ring_emit(ring, MI_WAIT_FOR_EVENT | MI_WAIT_FOR_OVERLAY_FLIP);
>+	}
> 	intel_ring_advance(ring);
> 
> 	return intel_overlay_do_wait_request(overlay, intel_overlay_off_tail);
>-- 
>1.7.11.4
>

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