Am Montag, den 02.10.2006, 11:24 +0200 schrieb Michel Dänzer:
> Hi Felix,
>
> On Sun, 2006-10-01 at 17:44 -0400, Felix Kühling wrote:
> >
> > 1: drm_lock.c: drm_unlock uses a new tasklet_lock. That leads to hangs
> > on my system (for some reason the driver can't find an IRQ for my PCI
> > card). Fortunately the NMI watchdog detects the lockup and kills the
> > Xserver, so I can recover the system without rebooting.
> >
> > I can see that tasklet_lock is only initialized in drm_irq_install and
> > only if the DRIVER_IRQ_VBL is enabled. Thus you can't unconditionally
> > use that spinlock in drm_unlock. The patch adds a condition
> > dev->irq_enabled, but I'm not sure if this is the right condition. I
> > believe dev->irq_enabled can be set even without DRIVER_IRQ_VBL being
> > enabled. Michel, what's would be the right way to handle this?
>
> I think initializing the spinlock unconditionally in drm_fill_in_dev()
> is the simplest solution. Fixed in
> 3a16e615cabfed18b1891a732e7243ef41dc0ad0.
Thanks, this fixes the problem for me.
Regards,
Felix
>
>
> > 2: drm_drawable.c: make idx and id signed integers in drm_rmdraw. There
> > are some comparisons such as id < 0 and idx >= 0 in there that don't
> > make sense for unsigned integers. And I actually got kernel oopses when
> > running glxinfo or glxgears in a naked Xserver when it destroyed the
> > last drawable. It crapped out here:
> >
> > ...
> > /* Can we shrink the arrays? */
> > if (idx == bitfield_length - 1) {
> > while (idx >= 0 && !bitfield[idx])
> > --idx;
> > ...
> >
> > idx will always be >= 0 if it's unsigned. --idx will make the value wrap
> > around and the next access to bitfield[idx] oopses.
>
> Good catch! I must have been 'lucky' for never hitting this on my
> development machine, but I'm also slightly disappointed that gcc didn't
> warn about it. Anyway, I pushed your fix as
> d58389968124191a546a14b42ef84edc224be23d.
>
>
> Thanks for the detailed report,
>
>
--
| Felix Kühling <[EMAIL PROTECTED]> http://fxk.de.vu |
| PGP Fingerprint: 6A3C 9566 5B30 DDED 73C3 B152 151C 5CC1 D888 E595 |
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