From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vasily Khoruzhick Subject: Re: Major 2.6.38 / 2.6.39 / 3.0 regression ignored? Date: Tue, 9 Aug 2011 17:00:52 +0300 Message-ID: <201108091700.53131.anarsoul@gmail.com> References: <013811$4lfs6@fmsmga002.fm.intel.com> <20110726134827.GA23696@tugrik.mns.mnsspb.ru> <20110809120803.GA15844@tugrik.mns.mnsspb.ru> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20110809120803.GA15844@tugrik.mns.mnsspb.ru> 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: intel-gfx@lists.freedesktop.org Cc: Pekka Enberg , Herbert Xu , Luke-Jr , LKML , dri-devel@lists.freedesktop.org, "Rafael J. Wysocki" , Ray Lee , Andrew Morton , Linus Torvalds List-Id: dri-devel@lists.freedesktop.org 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. Regards Vasily