On Wed, Oct 20, 2010 at 4:44 AM, Arnd Bergmann <arnd@xxxxxxxx> wrote: > On Tuesday 19 October 2010 22:29:12 Greg KH wrote: >> On Tue, Oct 19, 2010 at 09:40:47PM +0200, Oliver Neukum wrote: >> > Am Dienstag, 19. Oktober 2010, 21:37:35 schrieb Greg KH: >> > > > So no need to clean it up for multiprocessor support. >> > > > >> > > > http://download.intel.com/design/chipsets/datashts/29067602.pdf >> > > > http://www.intel.com/design/chipsets/specupdt/29069403.pdf >> > > >> > > Great, we can just drop all calls to lock_kernel() and the like in the >> > > driver and be done with it, right? >> > >> > No, >> > >> > you still need to switch off preemption. >> >> Hm, how would you do that from within a driver? > > I think this would do: > --- > drm/i810: remove SMP support and BKL > > The i810 and i815 chipsets supported by the i810 drm driver were not > officially designed for SMP operation, so the big kernel lock is > only required for kernel preemption. This disables the driver if > preemption is enabled and removes all calls to lock_kernel in it. > > If you own an Acorp 6A815EPD mainboard with a i815 chipset and > two Pentium-III sockets, and want to run recent kernels on it, > tell me about it. > > Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> > --- > > diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig > index b755301..e071bc8 100644 > --- a/drivers/gpu/drm/Kconfig > +++ b/drivers/gpu/drm/Kconfig > @@ -73,8 +73,8 @@ source "drivers/gpu/drm/radeon/Kconfig" > > Âconfig DRM_I810 > Â Â Â Âtristate "Intel I810" > - Â Â Â # BKL usage in order to avoid AB-BA deadlocks, may become BROKEN_ON_SMP > - Â Â Â depends on DRM && AGP && AGP_INTEL && BKL > + Â Â Â # PREEMPT requires BKL support here, which was removed > + Â Â Â depends on DRM && AGP && AGP_INTEL && !PREEMPT be curious, why can't just fix the lock_kernel logic of i810? Fixing is too hard? Find a i810 hardware should be possible, even if the hardware does not support SMP, can't we test the fix with preemption? -- Regards dave _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
