Messages in this thread | | | From | Chris Wilson <> | Subject | Re: 3.5 regression on i915 | Date | Sat, 06 Oct 2012 09:04:34 +0100 |
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On Sat, 6 Oct 2012 01:42:18 +0200, Willy Tarreau <w@1wt.eu> wrote: > Chris, Daniel, > > since version 3.5, my Asus EeePC 1005HA bugs during startx. I didn't > have the time to investigate until this evening. > > I could bisect the commits and found that the following one was merged > in 3.5-rc1 and is responsible for these bugs that can reliably be > triggered : > > 1b50247a8ddde4af5aaa0e6bc125615372ce6c16 is the first bad commit > commit 1b50247a8ddde4af5aaa0e6bc125615372ce6c16 > Author: Chris Wilson <chris@chris-wilson.co.uk> > Date: Tue Apr 24 15:47:30 2012 +0100 > > drm/i915: Remove the list of pinned inactive objects > > Simplify object tracking by removing the inactive but pinned list. The > only place where this was used is for counting the available memory, > which is just as easy performed by checking all objects on the rare > occasions it is required (application startup). For ease of debugging, > we keep the reporting of pinned objects through the error-state and > debugfs. > > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> > Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> > > I tried to revert it from 3.5.6-rc1 but it does not revert cleanly at all > and I'm totall unfamiliar with this code to attempt anything sane at this > time of the night. > > The crash happens here in i915_gem_entervt_ioctl() : > > 3659 BUG_ON(!list_empty(&dev_priv->mm.active_list)); > 3660 BUG_ON(!list_empty(&dev_priv->mm.flushing_list)); > -> 3661 BUG_ON(!list_empty(&dev_priv->mm.inactive_list)); > 3662 mutex_unlock(&dev->struct_mutex);
That BUG_ON there is silly and can simply be removed. The check is to verify that no batches were submitted to the kernel whilst the UMS/GEM client was suspended - to which the BUG_ONs are a crude approximation. Furthermore, the checks are too late, since it means we attempted to program the hardware whilst it was in an invalid state, the BUG_ONs are the least of your concerns at that point. -Chris
-- Chris Wilson, Intel Open Source Technology Centre
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