| Message ID | 1426768264-16996-56-git-send-email-John.C.Harrison@Intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
> -----Original Message----- > From: Intel-gfx [mailto:intel-gfx-bounces@lists.freedesktop.org] On Behalf Of > John.C.Harrison@Intel.com > Sent: Thursday, March 19, 2015 12:31 PM > To: Intel-GFX@Lists.FreeDesktop.Org > Subject: [Intel-gfx] [PATCH 55/59] drm/i915: Remove fallback poll for ring buffer > space > > From: John Harrison <John.C.Harrison@Intel.com> > > When the ring buffer is full, the driver finds an outstanding request that will > free up sufficient space for the current operation and waits for it to complete. > If no such request can be found, there is a fall back path of just polling until > sufficient space is available. > > This path should not be required any more. It is a hangover from the bad days of > OLR such that it was possible for the ring to be completely filled without ever > having submitted a request. This can no longer happen as requests are now > submitted in a timely manner. Hence the entire polling path is obsolete. As it > also causes headaches in LRC land due to nesting faked requests, it is being > removed entirely. > > For: VIZ-5115 > Signed-off-by: John Harrison <John.C.Harrison@Intel.com> > --- > drivers/gpu/drm/i915/intel_lrc.c | 65 ++++--------------------------- > drivers/gpu/drm/i915/intel_ringbuffer.c | 62 +++-------------------------- > 2 files changed, 13 insertions(+), 114 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c > index 60bcf9a..f21f449 100644 > --- a/drivers/gpu/drm/i915/intel_lrc.c > +++ b/drivers/gpu/drm/i915/intel_lrc.c > @@ -622,8 +622,9 @@ int intel_logical_ring_alloc_request_extras(struct > drm_i915_gem_request *request > return 0; > } > > -static int logical_ring_wait_request(struct intel_ringbuffer *ringbuf, > - int bytes) > +static int logical_ring_wait_for_space(struct intel_ringbuffer *ringbuf, > + struct intel_context *ctx, > + int bytes) > { > struct intel_engine_cs *ring = ringbuf->ring; > struct drm_i915_gem_request *request; > @@ -652,8 +653,11 @@ static int logical_ring_wait_request(struct > intel_ringbuffer *ringbuf, > break; > } > > - if (&request->list == &ring->request_list) > + /* It should always be possible to find a suitable request! */ > + if (&request->list == &ring->request_list) { > + WARN_ON(true); > return -ENOSPC; > + } Don’t we normally say if (WARN_ON(&request->list == &ring->request_list)) return -ENOSPC; > > ret = i915_wait_request(request); > if (ret) > @@ -663,7 +667,7 @@ static int logical_ring_wait_request(struct > intel_ringbuffer *ringbuf, > > WARN_ON(intel_ring_space(ringbuf) < new_space); > > - return intel_ring_space(ringbuf) >= bytes ? 0 : -ENOSPC; > + return 0; > } > > /* > @@ -690,59 +694,6 @@ intel_logical_ring_advance_and_submit(struct > intel_ringbuffer *ringbuf, > execlists_context_queue(ring, ctx, ringbuf->tail, request); > } > > -static int logical_ring_wait_for_space(struct intel_ringbuffer *ringbuf, > - struct intel_context *ctx, > - int bytes) > -{ > - struct intel_engine_cs *ring = ringbuf->ring; > - struct drm_device *dev = ring->dev; > - struct drm_i915_private *dev_priv = dev->dev_private; > - unsigned long end; > - int ret; > - > - /* The whole point of reserving space is to not wait! */ > - WARN_ON(ringbuf->reserved_in_use); > - > - ret = logical_ring_wait_request(ringbuf, bytes); > - if (ret != -ENOSPC) > - return ret; > - > - /* Force the context submission in case we have been skipping it */ > - intel_logical_ring_advance_and_submit(ringbuf, ctx, NULL); > - > - /* With GEM the hangcheck timer should kick us out of the loop, > - * leaving it early runs the risk of corrupting GEM state (due > - * to running on almost untested codepaths). But on resume > - * timers don't work yet, so prevent a complete hang in that > - * case by choosing an insanely large timeout. */ > - end = jiffies + 60 * HZ; > - > - ret = 0; > - do { > - if (intel_ring_space(ringbuf) >= bytes) > - break; > - > - msleep(1); > - > - if (dev_priv->mm.interruptible && signal_pending(current)) { > - ret = -ERESTARTSYS; > - break; > - } > - > - ret = i915_gem_check_wedge(&dev_priv->gpu_error, > - dev_priv->mm.interruptible); > - if (ret) > - break; > - > - if (time_after(jiffies, end)) { > - ret = -EBUSY; > - break; > - } > - } while (1); > - > - return ret; > -} > - > static int logical_ring_wrap_buffer(struct intel_ringbuffer *ringbuf, > struct intel_context *ctx) > { > diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c > b/drivers/gpu/drm/i915/intel_ringbuffer.c > index c5752c4..6099fce 100644 > --- a/drivers/gpu/drm/i915/intel_ringbuffer.c > +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c > @@ -2063,7 +2063,7 @@ void intel_cleanup_ring_buffer(struct intel_engine_cs > *ring) > ring->buffer = NULL; > } > > -static int intel_ring_wait_request(struct intel_engine_cs *ring, int n) > +static int ring_wait_for_space(struct intel_engine_cs *ring, int n) > { > struct intel_ringbuffer *ringbuf = ring->buffer; > struct drm_i915_gem_request *request; > @@ -2082,8 +2082,11 @@ static int intel_ring_wait_request(struct > intel_engine_cs *ring, int n) > break; > } > > - if (&request->list == &ring->request_list) > + /* It should always be possible to find a suitable request! */ > + if (&request->list == &ring->request_list) { > + WARN_ON(true); > return -ENOSPC; > + } Same thing. Thomas. > > ret = i915_wait_request(request); > if (ret) > @@ -2096,61 +2099,6 @@ static int intel_ring_wait_request(struct > intel_engine_cs *ring, int n) > return 0; > } > > -static int ring_wait_for_space(struct intel_engine_cs *ring, int n) > -{ > - struct drm_device *dev = ring->dev; > - struct drm_i915_private *dev_priv = dev->dev_private; > - struct intel_ringbuffer *ringbuf = ring->buffer; > - unsigned long end; > - int ret; > - > - /* The whole point of reserving space is to not wait! */ > - WARN_ON(ringbuf->reserved_in_use); > - > - ret = intel_ring_wait_request(ring, n); > - if (ret != -ENOSPC) > - return ret; > - > - /* force the tail write in case we have been skipping them */ > - __intel_ring_advance(ring); > - > - /* With GEM the hangcheck timer should kick us out of the loop, > - * leaving it early runs the risk of corrupting GEM state (due > - * to running on almost untested codepaths). But on resume > - * timers don't work yet, so prevent a complete hang in that > - * case by choosing an insanely large timeout. */ > - end = jiffies + 60 * HZ; > - > - ret = 0; > - trace_i915_ring_wait_begin(ring); > - do { > - if (intel_ring_space(ringbuf) >= n) > - break; > - ringbuf->head = I915_READ_HEAD(ring); > - if (intel_ring_space(ringbuf) >= n) > - break; > - > - msleep(1); > - > - if (dev_priv->mm.interruptible && signal_pending(current)) { > - ret = -ERESTARTSYS; > - break; > - } > - > - ret = i915_gem_check_wedge(&dev_priv->gpu_error, > - dev_priv->mm.interruptible); > - if (ret) > - break; > - > - if (time_after(jiffies, end)) { > - ret = -EBUSY; > - break; > - } > - } while (1); > - trace_i915_ring_wait_end(ring); > - return ret; > -} > - > static int intel_wrap_ring_buffer(struct intel_engine_cs *ring) > { > uint32_t __iomem *virt; > -- > 1.7.9.5 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
On Thu, 19 Mar 2015, "Daniel, Thomas" <thomas.daniel@intel.com> wrote: >> - if (&request->list == &ring->request_list) >> + /* It should always be possible to find a suitable request! */ >> + if (&request->list == &ring->request_list) { >> + WARN_ON(true); >> return -ENOSPC; >> + } > Don’t we normally say > if (WARN_ON(&request->list == &ring->request_list)) > return -ENOSPC; Yes, particularly since we've amended WARN_ON within i915 to print out the condition that failed. "true" is not very useful with that. ;) BR, Jani.
On 19/03/2015 15:16, Jani Nikula wrote: > On Thu, 19 Mar 2015, "Daniel, Thomas" <thomas.daniel@intel.com> wrote: >>> - if (&request->list == &ring->request_list) >>> + /* It should always be possible to find a suitable request! */ >>> + if (&request->list == &ring->request_list) { >>> + WARN_ON(true); >>> return -ENOSPC; >>> + } >> Don’t we normally say >> if (WARN_ON(&request->list == &ring->request_list)) >> return -ENOSPC; > Yes, particularly since we've amended WARN_ON within i915 to print out > the condition that failed. "true" is not very useful with that. ;) > > BR, > Jani. > The issue I have with 'if(WARN_ON(x))' is that it looks like something that would disappear in a non debugging build. Whereas, this is a check that wants to exist regardless of build options.
On Thu, Mar 19, 2015 at 04:33:12PM +0000, John Harrison wrote: > On 19/03/2015 15:16, Jani Nikula wrote: > >On Thu, 19 Mar 2015, "Daniel, Thomas" <thomas.daniel@intel.com> wrote: > >>>- if (&request->list == &ring->request_list) > >>>+ /* It should always be possible to find a suitable request! */ > >>>+ if (&request->list == &ring->request_list) { > >>>+ WARN_ON(true); > >>> return -ENOSPC; > >>>+ } > >>Don’t we normally say > >> if (WARN_ON(&request->list == &ring->request_list)) > >> return -ENOSPC; > >Yes, particularly since we've amended WARN_ON within i915 to print out > >the condition that failed. "true" is not very useful with that. ;) > > > >BR, > >Jani. > > > The issue I have with 'if(WARN_ON(x))' is that it looks like something that > would disappear in a non debugging build. Whereas, this is a check that > wants to exist regardless of build options. Yeah kernel isn't like that, WARN_ON is always executed. We rely on that all over the place actually by sometimes wrapping full function-calls with side-effects with a WARN_ON for cases we don't expect anything to ever fail. -Daniel
On 19/03/2015 12:31, John.C.Harrison@Intel.com wrote: > From: John Harrison <John.C.Harrison@Intel.com> > > When the ring buffer is full, the driver finds an outstanding request that will > free up sufficient space for the current operation and waits for it to complete. > If no such request can be found, there is a fall back path of just polling until > sufficient space is available. > > This path should not be required any more. It is a hangover from the bad days of > OLR such that it was possible for the ring to be completely filled without ever > having submitted a request. This can no longer happen as requests are now > submitted in a timely manner. Hence the entire polling path is obsolete. As it > also causes headaches in LRC land due to nesting faked requests, it is being > removed entirely. > > For: VIZ-5115 > Signed-off-by: John Harrison <John.C.Harrison@Intel.com> > --- > drivers/gpu/drm/i915/intel_lrc.c | 65 ++++--------------------------- > drivers/gpu/drm/i915/intel_ringbuffer.c | 62 +++-------------------------- > 2 files changed, 13 insertions(+), 114 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c > index 60bcf9a..f21f449 100644 > --- a/drivers/gpu/drm/i915/intel_lrc.c > +++ b/drivers/gpu/drm/i915/intel_lrc.c > @@ -622,8 +622,9 @@ int intel_logical_ring_alloc_request_extras(struct drm_i915_gem_request *request > return 0; > } > > -static int logical_ring_wait_request(struct intel_ringbuffer *ringbuf, > - int bytes) > +static int logical_ring_wait_for_space(struct intel_ringbuffer *ringbuf, > + struct intel_context *ctx, > + int bytes) > { > struct intel_engine_cs *ring = ringbuf->ring; > struct drm_i915_gem_request *request; > @@ -652,8 +653,11 @@ static int logical_ring_wait_request(struct intel_ringbuffer *ringbuf, > break; > } > > - if (&request->list == &ring->request_list) > + /* It should always be possible to find a suitable request! */ > + if (&request->list == &ring->request_list) { > + WARN_ON(true); I agree with Thomas Daniel's earlier review comment that WARN_ON(true) is not very helpful. You could do something like: WARN_ON(ret = <expression>); if (ret) return -ENOSPC; That way you don't have the redundancy of doing WARN_ON(expression); if (expression) return -ENOSPC; and you don't have to do if (WARN_ON(expression)) if you don't like it. Thanks, Tomas > return -ENOSPC; > + } > > ret = i915_wait_request(request); > if (ret) > @@ -663,7 +667,7 @@ static int logical_ring_wait_request(struct intel_ringbuffer *ringbuf, > > WARN_ON(intel_ring_space(ringbuf) < new_space); > > - return intel_ring_space(ringbuf) >= bytes ? 0 : -ENOSPC; > + return 0; > } > > /* > @@ -690,59 +694,6 @@ intel_logical_ring_advance_and_submit(struct intel_ringbuffer *ringbuf, > execlists_context_queue(ring, ctx, ringbuf->tail, request); > } > > -static int logical_ring_wait_for_space(struct intel_ringbuffer *ringbuf, > - struct intel_context *ctx, > - int bytes) > -{ > - struct intel_engine_cs *ring = ringbuf->ring; > - struct drm_device *dev = ring->dev; > - struct drm_i915_private *dev_priv = dev->dev_private; > - unsigned long end; > - int ret; > - > - /* The whole point of reserving space is to not wait! */ > - WARN_ON(ringbuf->reserved_in_use); > - > - ret = logical_ring_wait_request(ringbuf, bytes); > - if (ret != -ENOSPC) > - return ret; > - > - /* Force the context submission in case we have been skipping it */ > - intel_logical_ring_advance_and_submit(ringbuf, ctx, NULL); > - > - /* With GEM the hangcheck timer should kick us out of the loop, > - * leaving it early runs the risk of corrupting GEM state (due > - * to running on almost untested codepaths). But on resume > - * timers don't work yet, so prevent a complete hang in that > - * case by choosing an insanely large timeout. */ > - end = jiffies + 60 * HZ; > - > - ret = 0; > - do { > - if (intel_ring_space(ringbuf) >= bytes) > - break; > - > - msleep(1); > - > - if (dev_priv->mm.interruptible && signal_pending(current)) { > - ret = -ERESTARTSYS; > - break; > - } > - > - ret = i915_gem_check_wedge(&dev_priv->gpu_error, > - dev_priv->mm.interruptible); > - if (ret) > - break; > - > - if (time_after(jiffies, end)) { > - ret = -EBUSY; > - break; > - } > - } while (1); > - > - return ret; > -} > - > static int logical_ring_wrap_buffer(struct intel_ringbuffer *ringbuf, > struct intel_context *ctx) > { > diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c > index c5752c4..6099fce 100644 > --- a/drivers/gpu/drm/i915/intel_ringbuffer.c > +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c > @@ -2063,7 +2063,7 @@ void intel_cleanup_ring_buffer(struct intel_engine_cs *ring) > ring->buffer = NULL; > } > > -static int intel_ring_wait_request(struct intel_engine_cs *ring, int n) > +static int ring_wait_for_space(struct intel_engine_cs *ring, int n) > { > struct intel_ringbuffer *ringbuf = ring->buffer; > struct drm_i915_gem_request *request; > @@ -2082,8 +2082,11 @@ static int intel_ring_wait_request(struct intel_engine_cs *ring, int n) > break; > } > > - if (&request->list == &ring->request_list) > + /* It should always be possible to find a suitable request! */ > + if (&request->list == &ring->request_list) { > + WARN_ON(true); > return -ENOSPC; > + } > > ret = i915_wait_request(request); > if (ret) > @@ -2096,61 +2099,6 @@ static int intel_ring_wait_request(struct intel_engine_cs *ring, int n) > return 0; > } > > -static int ring_wait_for_space(struct intel_engine_cs *ring, int n) > -{ > - struct drm_device *dev = ring->dev; > - struct drm_i915_private *dev_priv = dev->dev_private; > - struct intel_ringbuffer *ringbuf = ring->buffer; > - unsigned long end; > - int ret; > - > - /* The whole point of reserving space is to not wait! */ > - WARN_ON(ringbuf->reserved_in_use); > - > - ret = intel_ring_wait_request(ring, n); > - if (ret != -ENOSPC) > - return ret; > - > - /* force the tail write in case we have been skipping them */ > - __intel_ring_advance(ring); > - > - /* With GEM the hangcheck timer should kick us out of the loop, > - * leaving it early runs the risk of corrupting GEM state (due > - * to running on almost untested codepaths). But on resume > - * timers don't work yet, so prevent a complete hang in that > - * case by choosing an insanely large timeout. */ > - end = jiffies + 60 * HZ; > - > - ret = 0; > - trace_i915_ring_wait_begin(ring); > - do { > - if (intel_ring_space(ringbuf) >= n) > - break; > - ringbuf->head = I915_READ_HEAD(ring); > - if (intel_ring_space(ringbuf) >= n) > - break; > - > - msleep(1); > - > - if (dev_priv->mm.interruptible && signal_pending(current)) { > - ret = -ERESTARTSYS; > - break; > - } > - > - ret = i915_gem_check_wedge(&dev_priv->gpu_error, > - dev_priv->mm.interruptible); > - if (ret) > - break; > - > - if (time_after(jiffies, end)) { > - ret = -EBUSY; > - break; > - } > - } while (1); > - trace_i915_ring_wait_end(ring); > - return ret; > -} > - > static int intel_wrap_ring_buffer(struct intel_engine_cs *ring) > { > uint32_t __iomem *virt; >
On Tue, Mar 31, 2015 at 07:13:40PM +0100, Tomas Elf wrote: > On 19/03/2015 12:31, John.C.Harrison@Intel.com wrote: > >From: John Harrison <John.C.Harrison@Intel.com> > >@@ -652,8 +653,11 @@ static int logical_ring_wait_request(struct intel_ringbuffer *ringbuf, > > break; > > } > > > >- if (&request->list == &ring->request_list) > >+ /* It should always be possible to find a suitable request! */ > >+ if (&request->list == &ring->request_list) { > >+ WARN_ON(true); > > I agree with Thomas Daniel's earlier review comment that WARN_ON(true) is > not very helpful. You could do something like: > > WARN_ON(ret = <expression>); > if (ret) > return -ENOSPC; > > That way you don't have the redundancy of doing > > WARN_ON(expression); > if (expression) > return -ENOSPC; > > > and you don't have to do if (WARN_ON(expression)) if you don't like it. if (WARN_ON(expression)) is prefectly acceptable style in i915 (there's lots more of these) and what I'd go with here. -Daniel
On Tue, Mar 31, 2015 at 07:13:40PM +0100, Tomas Elf wrote: > On 19/03/2015 12:31, John.C.Harrison@Intel.com wrote: > >From: John Harrison <John.C.Harrison@Intel.com> > > > >When the ring buffer is full, the driver finds an outstanding request that will > >free up sufficient space for the current operation and waits for it to complete. > >If no such request can be found, there is a fall back path of just polling until > >sufficient space is available. > > > >This path should not be required any more. It is a hangover from the bad days of > >OLR such that it was possible for the ring to be completely filled without ever > >having submitted a request. No. This is wrong. It is from DRI1. We never could have touched the ring without an OLR. -Chris
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c index 60bcf9a..f21f449 100644 --- a/drivers/gpu/drm/i915/intel_lrc.c +++ b/drivers/gpu/drm/i915/intel_lrc.c @@ -622,8 +622,9 @@ int intel_logical_ring_alloc_request_extras(struct drm_i915_gem_request *request return 0; } -static int logical_ring_wait_request(struct intel_ringbuffer *ringbuf, - int bytes) +static int logical_ring_wait_for_space(struct intel_ringbuffer *ringbuf, + struct intel_context *ctx, + int bytes) { struct intel_engine_cs *ring = ringbuf->ring; struct drm_i915_gem_request *request; @@ -652,8 +653,11 @@ static int logical_ring_wait_request(struct intel_ringbuffer *ringbuf, break; } - if (&request->list == &ring->request_list) + /* It should always be possible to find a suitable request! */ + if (&request->list == &ring->request_list) { + WARN_ON(true); return -ENOSPC; + } ret = i915_wait_request(request); if (ret) @@ -663,7 +667,7 @@ static int logical_ring_wait_request(struct intel_ringbuffer *ringbuf, WARN_ON(intel_ring_space(ringbuf) < new_space); - return intel_ring_space(ringbuf) >= bytes ? 0 : -ENOSPC; + return 0; } /* @@ -690,59 +694,6 @@ intel_logical_ring_advance_and_submit(struct intel_ringbuffer *ringbuf, execlists_context_queue(ring, ctx, ringbuf->tail, request); } -static int logical_ring_wait_for_space(struct intel_ringbuffer *ringbuf, - struct intel_context *ctx, - int bytes) -{ - struct intel_engine_cs *ring = ringbuf->ring; - struct drm_device *dev = ring->dev; - struct drm_i915_private *dev_priv = dev->dev_private; - unsigned long end; - int ret; - - /* The whole point of reserving space is to not wait! */ - WARN_ON(ringbuf->reserved_in_use); - - ret = logical_ring_wait_request(ringbuf, bytes); - if (ret != -ENOSPC) - return ret; - - /* Force the context submission in case we have been skipping it */ - intel_logical_ring_advance_and_submit(ringbuf, ctx, NULL); - - /* With GEM the hangcheck timer should kick us out of the loop, - * leaving it early runs the risk of corrupting GEM state (due - * to running on almost untested codepaths). But on resume - * timers don't work yet, so prevent a complete hang in that - * case by choosing an insanely large timeout. */ - end = jiffies + 60 * HZ; - - ret = 0; - do { - if (intel_ring_space(ringbuf) >= bytes) - break; - - msleep(1); - - if (dev_priv->mm.interruptible && signal_pending(current)) { - ret = -ERESTARTSYS; - break; - } - - ret = i915_gem_check_wedge(&dev_priv->gpu_error, - dev_priv->mm.interruptible); - if (ret) - break; - - if (time_after(jiffies, end)) { - ret = -EBUSY; - break; - } - } while (1); - - return ret; -} - static int logical_ring_wrap_buffer(struct intel_ringbuffer *ringbuf, struct intel_context *ctx) { diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c index c5752c4..6099fce 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.c +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c @@ -2063,7 +2063,7 @@ void intel_cleanup_ring_buffer(struct intel_engine_cs *ring) ring->buffer = NULL; } -static int intel_ring_wait_request(struct intel_engine_cs *ring, int n) +static int ring_wait_for_space(struct intel_engine_cs *ring, int n) { struct intel_ringbuffer *ringbuf = ring->buffer; struct drm_i915_gem_request *request; @@ -2082,8 +2082,11 @@ static int intel_ring_wait_request(struct intel_engine_cs *ring, int n) break; } - if (&request->list == &ring->request_list) + /* It should always be possible to find a suitable request! */ + if (&request->list == &ring->request_list) { + WARN_ON(true); return -ENOSPC; + } ret = i915_wait_request(request); if (ret) @@ -2096,61 +2099,6 @@ static int intel_ring_wait_request(struct intel_engine_cs *ring, int n) return 0; } -static int ring_wait_for_space(struct intel_engine_cs *ring, int n) -{ - struct drm_device *dev = ring->dev; - struct drm_i915_private *dev_priv = dev->dev_private; - struct intel_ringbuffer *ringbuf = ring->buffer; - unsigned long end; - int ret; - - /* The whole point of reserving space is to not wait! */ - WARN_ON(ringbuf->reserved_in_use); - - ret = intel_ring_wait_request(ring, n); - if (ret != -ENOSPC) - return ret; - - /* force the tail write in case we have been skipping them */ - __intel_ring_advance(ring); - - /* With GEM the hangcheck timer should kick us out of the loop, - * leaving it early runs the risk of corrupting GEM state (due - * to running on almost untested codepaths). But on resume - * timers don't work yet, so prevent a complete hang in that - * case by choosing an insanely large timeout. */ - end = jiffies + 60 * HZ; - - ret = 0; - trace_i915_ring_wait_begin(ring); - do { - if (intel_ring_space(ringbuf) >= n) - break; - ringbuf->head = I915_READ_HEAD(ring); - if (intel_ring_space(ringbuf) >= n) - break; - - msleep(1); - - if (dev_priv->mm.interruptible && signal_pending(current)) { - ret = -ERESTARTSYS; - break; - } - - ret = i915_gem_check_wedge(&dev_priv->gpu_error, - dev_priv->mm.interruptible); - if (ret) - break; - - if (time_after(jiffies, end)) { - ret = -EBUSY; - break; - } - } while (1); - trace_i915_ring_wait_end(ring); - return ret; -} - static int intel_wrap_ring_buffer(struct intel_engine_cs *ring) { uint32_t __iomem *virt;