Attachment 104224 Details for Bug 76554 – [PATCH] drm/i915: read HEAD register back in init_ring_common() to enforce ordering

[patch] [PATCH] drm/i915: read HEAD register back in init_ring_common() to enforce ordering

0001-drm-i915-read-HEAD-register-back-in-init_ring_common.patch (text/plain), 1.19 KB, created by Jiri Kosina on 2014-08-07 12:22:29 UTC

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Creator: Jiri Kosina

Created: 2014-08-07 12:22:29 UTC

Size: 1.19 KB

patch

obsolete

>From a4acb8d0933f89eca6c26c2d3da39e6294e4fb98 Mon Sep 17 00:00:00 2001
>From: Jiri Kosina <jkosina@suse.cz>
>Date: Thu, 7 Aug 2014 14:04:09 +0200
>Subject: [PATCH] drm/i915: read HEAD register back in init_ring_common() to
> enforce ordering
>
>Withtout this, ring initialization fails reliabily during resume with
>
>	[drm:init_ring_common] *ERROR* render ring initialization failed ctl 0001f001 head ffffff8804 tail 00000000 start 000e4000
>
>Signed-off-by: Jiri Kosina <jkosina@suse.cz>
>---
> drivers/gpu/drm/i915/intel_ringbuffer.c | 3 +++
> 1 file changed, 3 insertions(+)
>
>diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
>index 279488a..7add7ee 100644
>--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
>+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
>@@ -517,6 +517,9 @@ static int init_ring_common(struct intel_engine_cs *ring)
> 	else
> 		ring_setup_phys_status_page(ring);
> 
>+	/* Enforce ordering by reading HEAD register back */
>+	I915_READ_HEAD(ring);
>+
> 	/* Initialize the ring. This must happen _after_ we've cleared the ring
> 	 * registers with the above sequence (the readback of the HEAD registers
> 	 * also enforces ordering), otherwise the hw might lose the new ring
>-- 
>1.8.5.2
>

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Attachments on bug 76554: 96294 | 96298 | 96304 | 96305 | 96307 | 96311 | 96323 | 96406 | 96776 | 96783 | 97027 | 97034 | 97035 | 97036 | 97739 | 97744 | 97747 | 97756 | 97774 | 99172 | 104181 | 104208 | 104212 | 104216 | 104224 | 104226 | 104227 | 106514 | 107730

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