From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Widawsky Subject: Re: [PATCH 1/5] drm/i915: kicking rings stuck on semaphores considered harmful Date: Sun, 30 Oct 2011 18:25:46 -0700 Message-ID: <20111030182546.15e14a1c@bwidawsk.net> References: <1320001932-1846-1-git-send-email-daniel.vetter@ffwll.ch> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from cloud01.chad-versace.us (184-106-247-128.static.cloud-ips.com [184.106.247.128]) by gabe.freedesktop.org (Postfix) with ESMTP id 13A059E8BC for ; Sun, 30 Oct 2011 18:26:03 -0700 (PDT) In-Reply-To: <1320001932-1846-1-git-send-email-daniel.vetter@ffwll.ch> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org Errors-To: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org To: Daniel Vetter Cc: intel-gfx List-Id: intel-gfx@lists.freedesktop.org On Sun, 30 Oct 2011 20:12:08 +0100 Daniel Vetter wrote: > If our semaphore logic gets confused and we have a ring stuck waiting > for one, there's a decent chance it'll just execute garbage when being > kicked. Also, kicking the ring obscures the place where the error > first occured, making error_state decoding much harder. > > So drop this an let gpu reset handle this mess in a clean fashion. > > In contrast, kicking rings stuck on MI_WAIT is rather harmless, at > worst there'll be a bit of screen-flickering. There's also old > broken userspace out there which needs this as a work-around. > > Signed-off-by: Daniel Vetter > Reviewed-by: Chris Wilson > Reviewed-by: Ben Widawsky > --- > drivers/gpu/drm/i915/i915_irq.c | 7 ------- > 1 files changed, 0 insertions(+), 7 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c > index b40004b..69d4044 100644 > --- a/drivers/gpu/drm/i915/i915_irq.c > +++ b/drivers/gpu/drm/i915/i915_irq.c > @@ -1649,13 +1649,6 @@ static bool kick_ring(struct intel_ring_buffer *ring) > I915_WRITE_CTL(ring, tmp); > return true; > } > - if (IS_GEN6(dev) && > - (tmp & RING_WAIT_SEMAPHORE)) { > - DRM_ERROR("Kicking stuck semaphore on %s\n", > - ring->name); > - I915_WRITE_CTL(ring, tmp); > - return true; > - } > return false; > } > This also has the added benefit that it fixes a forcewake race on gen6+. Ben