From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kirill Smelkov Subject: Re: Major 2.6.38 / 2.6.39 / 3.0 regression ignored? Date: Tue, 9 Aug 2011 19:34:46 +0400 Message-ID: <20110809153446.GA22077@tugrik.mns.mnsspb.ru> References: <013811$4lfs6@fmsmga002.fm.intel.com> <201108091700.53131.anarsoul@gmail.com> <20110809144755.GA12754@tugrik.mns.mnsspb.ru> <201108091809.58425.anarsoul@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <201108091809.58425.anarsoul@gmail.com> 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: Vasily Khoruzhick Cc: Pekka Enberg , Herbert Xu , Luke-Jr , intel-gfx@lists.freedesktop.org, LKML , dri-devel@lists.freedesktop.org, "Rafael J. Wysocki" , Ray Lee , Andrew Morton , Linus Torvalds List-Id: dri-devel@lists.freedesktop.org On Tue, Aug 09, 2011 at 06:09:57PM +0300, Vasily Khoruzhick wrote: > On Tuesday 09 August 2011 17:47:56 Kirill Smelkov wrote: > > On Tue, Aug 09, 2011 at 05:00:52PM +0300, Vasily Khoruzhick wrote: > > > On Tuesday 09 August 2011 15:08:03 Kirill Smelkov wrote: > > > > On Tue, Jul 26, 2011 at 05:48:27PM +0400, Kirill Smelkov wrote: > > > > > On Sat, Jul 23, 2011 at 12:23:36AM +0400, Kirill Smelkov wrote: > > > > > > Keith, > > > > > > > > > > > > first of all thanks for your prompt reply. Then... > > > > > > > > > > > > On Fri, Jul 22, 2011 at 11:00:41AM -0700, Keith Packard wrote: > > > > > > > On Fri, 22 Jul 2011 15:08:06 +0400, Kirill Smelkov > > > > > > > > > > > > > wrote: > > > > > > > > And now after v3.0 is out, I've tested it again, and yes, like > > > > > > > > it was broken on v3.0-rc5, it is (now even more) broken on > > > > > > > > v3.0 -- after first > > > > > > > > > > > > > > > bad io access the system freezes completely: > > > > > > > I looked at this when I first saw it (a couple of weeks ago), and > > > > > > > I couldn't see any obvious reason this patch would cause this > > > > > > > particular problem. I didn't want to revert the patch at that > > > > > > > point as I feared it would cause other subtle problems. Given > > > > > > > that you've got a work-around, it seemed best to just push this > > > > > > > off past 3.0. > > > > > > > > > > > > What kind of a workaround are you talking about? Sorry, to me it > > > > > > all looked like "UMS is being ignored forever". Anyway, let's move > > > > > > on to try to solve the issue. > > > > > > > > > > > > > Given the failing address passed to ioread32, this seems like > > > > > > > it's probably the call to READ_BREADCRUMB -- > > > > > > > I915_BREADCRUMB_INDEX is 0x21, which is an offset in 32-bit > > > > > > > units within the hardware status page. If the > > > > > > > status_page.page_addr value was zero, then the computed address > > > > > > > would end up being 0x84. > > > > > > > > > > > > > > And, it looks like status_page.page_addr *will* end up being zero > > > > > > > as a result of the patch in question. The patch resets the > > > > > > > entire ring structure contents back to the initial values, which > > > > > > > includes smashing the status_page structure to zero, clearing > > > > > > > the value of status_page.page_addr set in i915_init_phys_hws. > > > > > > > > > > > > > > Here's an untested patch which moves the initialization of > > > > > > > status_page.page_addr into intel_render_ring_init_dri. I note > > > > > > > that intel_init_render_ring_buffer *already* has the setting of > > > > > > > the status_page.page_addr value, and so I've removed the setting > > > > > > > of status_page.page_addr from i915_init_phys_hws. > > > > > > > > > > > > > > I suspect we could remove the memset from > > > > > > > intel_init_render_ring_buffer; it seems entirely superfluous > > > > > > > given the memset in i915_init_phys_hws. > > > > > > > > > > > > > > From 159ba1dd207fc52590ce8a3afd83f40bd2cedf46 Mon Sep 17 00:00:00 > > > > > > > 2001 From: Keith Packard > > > > > > > Date: Fri, 22 Jul 2011 10:44:39 -0700 > > > > > > > Subject: [PATCH] drm/i915: Initialize RCS ring status page > > > > > > > address in > > > > > > > > > > > > > > intel_render_ring_init_dri > > > > > > > > > > > > > > Physically-addressed hardware status pages are initialized early > > > > > > > in the driver load process by i915_init_phys_hws. For UMS > > > > > > > environments, the ring structure is not initialized until the X > > > > > > > server starts. At that point, the entire ring structure is > > > > > > > re-initialized with all new values. Any values set in the ring > > > > > > > structure (including > > > > > > > ring->status_page.page_addr) will be lost when the ring is > > > > > > > re-initialized. > > > > > > > > > > > > > > This patch moves the initialization of the status_page.page_addr > > > > > > > value to intel_render_ring_init_dri. > > > > > > > > > > > > > > Signed-off-by: Keith Packard > > > > > > > --- > > > > > > > > > > > > > > drivers/gpu/drm/i915/i915_dma.c | 6 ++---- > > > > > > > drivers/gpu/drm/i915/intel_ringbuffer.c | 3 +++ > > > > > > > 2 files changed, 5 insertions(+), 4 deletions(-) > > > > > > > > > > > > > > diff --git a/drivers/gpu/drm/i915/i915_dma.c > > > > > > > b/drivers/gpu/drm/i915/i915_dma.c index 1271282..8a3942c 100644 > > > > > > > --- a/drivers/gpu/drm/i915/i915_dma.c > > > > > > > +++ b/drivers/gpu/drm/i915/i915_dma.c > > > > > > > @@ -61,7 +61,6 @@ static void i915_write_hws_pga(struct > > > > > > > drm_device *dev) > > > > > > > > > > > > > > static int i915_init_phys_hws(struct drm_device *dev) > > > > > > > { > > > > > > > > > > > > > > drm_i915_private_t *dev_priv = dev->dev_private; > > > > > > > > > > > > > > - struct intel_ring_buffer *ring = LP_RING(dev_priv); > > > > > > > > > > > > > > /* Program Hardware Status Page */ > > > > > > > dev_priv->status_page_dmah = > > > > > > > > > > > > > > @@ -71,10 +70,9 @@ static int i915_init_phys_hws(struct > > > > > > > drm_device *dev) > > > > > > > > > > > > > > DRM_ERROR("Can not allocate hardware status page\n"); > > > > > > > return -ENOMEM; > > > > > > > > > > > > > > } > > > > > > > > > > > > > > - ring->status_page.page_addr = > > > > > > > - (void __force __iomem *)dev_priv->status_page_dmah->vaddr; > > > > > > > > > > > > > > - memset_io(ring->status_page.page_addr, 0, PAGE_SIZE); > > > > > > > + memset_io((void __force __iomem > > > > > > > *)dev_priv->status_page_dmah->vaddr, + 0, PAGE_SIZE); > > > > > > > > > > > > > > i915_write_hws_pga(dev); > > > > > > > > > > > > > > diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c > > > > > > > b/drivers/gpu/drm/i915/intel_ringbuffer.c index e961568..47b9b27 > > > > > > > 100644 > > > > > > > --- a/drivers/gpu/drm/i915/intel_ringbuffer.c > > > > > > > +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c > > > > > > > @@ -1321,6 +1321,9 @@ int intel_render_ring_init_dri(struct > > > > > > > drm_device *dev, u64 start, u32 size) > > > > > > > > > > > > > > ring->get_seqno = pc_render_get_seqno; > > > > > > > > > > > > > > } > > > > > > > > > > > > > > + if (!I915_NEED_GFX_HWS(dev)) > > > > > > > + ring->status_page.page_addr = > > > > > > > dev_priv->status_page_dmah->vaddr; + > > > > > > > > > > > > > > ring->dev = dev; > > > > > > > INIT_LIST_HEAD(&ring->active_list); > > > > > > > INIT_LIST_HEAD(&ring->request_list); > > > > > > > > > > > > I can't tell whether this is correct, because intel gfx driver is > > > > > > unknown to me, but from the first glance your description sounds > > > > > > reasonable. > > > > > > > > > > > > I'm out of office till ~ next week's tuesday, and on return I'll > > > > > > try to test it on the hardware in question. > > > > > > > > > > Keith, thanks again for the patch. As promised I've tested it on the > > > > > hardware in question and yes, bad_access is gone and X seems to work, > > > > > so thank you, but... > > > > > > > > > > > > > > > I see there are more such bugs in introduced-in-guilty-patch > > > > > intel_render_ring_init_dri(). For example ring->irq_queue is > > > > > left uninitialized and also ring->irq_lock etc... > > > > > > > > > > > > > > > I'm X newbie, so if here is something stupid X-wise, please don't > > > > > beat me too hard, but to me the gist of the problem is the original > > > > > patch, where Chris does > > > > > > > > > > ( git show e8616b6ced6137085e6657cc63bc2fe3900b8616 ) > > > > > > > > > > > diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c > > > > > > b/drivers/gpu/drm/i915/intel_ringbuffer.c index 03e3370..51fbc5e > > > > > > 100644 > > > > > > --- a/drivers/gpu/drm/i915/intel_ringbuffer.c > > > > > > +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c > > > > > > @@ -1291,6 +1291,48 @@ int intel_init_render_ring_buffer(struct > > > > > > drm_device *dev) > > > > > > > > > > > > return intel_init_ring_buffer(dev, ring); > > > > > > > > > > > > } > > > > > > > > > > > > +int intel_render_ring_init_dri(struct drm_device *dev, u64 start, > > > > > > u32 size) +{ > > > > > > + drm_i915_private_t *dev_priv = dev->dev_private; > > > > > > + struct intel_ring_buffer *ring = &dev_priv->ring[RCS]; > > > > > > + > > > > > > + *ring = render_ring; > > > > > > > > > > > ^^^^^^^^^^^^^^^^^^^ > > > > > here resets > > > > > > > > > > > > + if (INTEL_INFO(dev)->gen >= 6) { > > > > > > + ring->add_request = gen6_add_request; > > > > > > + ring->irq_get = gen6_render_ring_get_irq; > > > > > > + ring->irq_put = gen6_render_ring_put_irq; > > > > > > + } else if (IS_GEN5(dev)) { > > > > > > + ring->add_request = pc_render_add_request; > > > > > > + ring->get_seqno = pc_render_get_seqno; > > > > > > + } > > > > > > > > > > and then the rest of the `ring` is initialized seemingly copy-pasted > > > > > > > > > > from intel_init_ring_buffer(): > > > > > > + ring->dev = dev; > > > > > > + INIT_LIST_HEAD(&ring->active_list); > > > > > > + INIT_LIST_HEAD(&ring->request_list); > > > > > > + INIT_LIST_HEAD(&ring->gpu_write_list); > > > > > > + > > > > > > + ring->size = size; > > > > > > + ring->effective_size = ring->size; > > > > > > + if (IS_I830(ring->dev)) > > > > > > + ring->effective_size -= 128; > > > > > > + > > > > > > + ring->map.offset = start; > > > > > > + ring->map.size = size; > > > > > > + ring->map.type = 0; > > > > > > + ring->map.flags = 0; > > > > > > + ring->map.mtrr = 0; > > > > > > > > > > ... > > > > > > > > > > where both 3 chunks go almost exactly from intel_init_ring_buffer(), > > > > > and ring->effective_size tweak even stripped original comment: > > > > > > > > > > # original version from intel_init_ring_buffer(): > > > > > /* Workaround an erratum on the i830 which causes a hang if > > > > > > > > > > * the TAIL pointer points to within the last 2 cachelines > > > > > * of the buffer. > > > > > */ > > > > > > > > > > ring->effective_size = ring->size; > > > > > if (IS_I830(ring->dev)) > > > > > > > > > > ring->effective_size -= 128; > > > > > > > > > > ... > > > > > > > > > > > > > > > The line marked "here resets" resets all the fields, and maybe it's > > > > > not a good idea to re-initialize them all afterwards (missing some > > > > > as this thread show), or at least if it is really needed, share > > > > > initialization code between intel_render_ring_init_dri() and > > > > > intel_init_ring_buffer() ? > > > > > > > > > > >From the outside it looks like the offending patch was done as a > > > > > >quick > > > > > > > > > > fix in a hurry (lots of copy-paste), and maybe it would be better to > > > > > re-do it properly... > > > > > > > > Silence... ? > > > > > > > > I read UMS is still ignored, because e.g. that uninitialized > > > > ring->irq_lock which I've wrote about above is for sure used e.g. in > > > > gen6_render_ring_get_irq() added to ring vtable in > > > > intel_render_ring_init_dri(). > > > > > > I really doubt that UMS supports gen6 hardware. > > > > Then why it is there in intel_render_ring_init_dri(): > > > > int intel_render_ring_init_dri(struct drm_device *dev, u64 start, u32 > > size) { > > drm_i915_private_t *dev_priv = dev->dev_private; > > struct intel_ring_buffer *ring = &dev_priv->ring[RCS]; > > > > *ring = render_ring; > > if (INTEL_INFO(dev)->gen >= 6) { > > This branch executes only when hw generation is 6 or newer. and adds gen6_render_ring_get_irq() to vtable which uses ring->irq_lock which is left uninitialized. I don't understand what you were trying to say. How does it matter if some branch executes only for such-and-such hardware, when this branch contains bugs? Could you please clarify? > > ring->add_request = gen6_add_request; > > ring->irq_get = gen6_render_ring_get_irq; > > ring->irq_put = gen6_render_ring_put_irq; > > } else if (IS_GEN5(dev)) { > > ring->add_request = pc_render_add_request; > > ring->get_seqno = pc_render_get_seqno; > > }