On Sun, 2009-07-05 at 18:18 +0200, Krzysztof Helt wrote:
> On Mon, 6 Jul 2009 00:25:57 +0900
> Paul Mundt <email@example.com> wrote:
> > On Sun, Jul 05, 2009 at 08:19:40AM -0700, Linus Torvalds wrote:
> > >
> > >
> > > On Mon, 6 Jul 2009, Paul Mundt wrote:
> > > > >
> > > > > Why not "lock" as well?
> > > >
> > > > I had that initially, but matroxfb will break if we do that, and
> > > > presently nothing cares about trying to take ->lock that early on.
> > >
> > > I really would rather have consistency than some odd rules like that.
> > >
> > > In particular - if matroxfb is different and needs its own lock
> > > initialization because it doesn't use the common allocation routine, then
> > > please make _that_ consistent too. Rather than have it special-case just
> > > one lock that it needs to initialize separately, make it clear that since
> > > it does its own allocations it needs to initialize _everything_
> > > separately.
> > >
> > Ok, here is an updated version with an updated matroxfb and the sm501fb
> > change reverted.
> > Signed-off-by: Paul Mundt <firstname.lastname@example.org>
> > ---
> This is incorrect way to fix this as some drivers do not use the
> at all. They use global (for a file) fb_info structure. I have done some
> cleanups to
> the fbdev layer before the 2.6.31 and there should no drivers which uses
> kmalloc or
> kzalloc to allocate the fb_info (your patch would break these drivers too).
> A root of the whole mm_lock issue is that the fb_mmap() BKL protected two
> fields which were never protected when set. I changed this by add the mm_lock
> around these fields but only in drivers which modified this fields AFTER call
> to the register_framebuffer(). Some drivers set these fields using the same
> function before and after the register_framebuffer(). I strongly believe that
> setting these fields before the register_framebuffer() is wrong or redundant
> these drivers. See my fix for the sisfb driver below.
> I have tested the patch below. Wu Zhangjin, can you also confirm that this
> works for you (without your patch)?
This patch also works for me, thanks!
> I will look into the matroxfb and sm501fb drivers now. The same problem is
> already fixed for the mx3fb driver and the patch is sent to Andrew Morton.
> From: Krzysztof Helt <email@example.com>
> Remove redundant call to the sisfb_get_fix() before sis frambuffer is
> This fixes a problem with uninitialized the fb_info->mm_lock mutex.
> Signed-off-by: Krzysztof Helt <firstname.lastname@example.org>
> diff -urp linux-ref/drivers/video/sis/sis_main.c
> --- linux-ref/drivers/video/sis/sis_main.c 2009-07-01 18:07:05.000000000
> +++ linux-next/drivers/video/sis/sis_main.c 2009-07-05 17:20:33.000000000
> @@ -6367,7 +6367,6 @@ error_3: vfree(ivideo->bios_abase);
> sis_fb_info->fix = ivideo->sisfb_fix;
> sis_fb_info->screen_base = ivideo->video_vbase +
> sis_fb_info->fbops = &sisfb_ops;
> - sisfb_get_fix(&sis_fb_info->fix, -1, sis_fb_info);
> sis_fb_info->pseudo_palette = ivideo->pseudo_palette;
> fb_alloc_cmap(&sis_fb_info->cmap, 256 , 0);
> Najlepsze OC i AC tylko w Ergo Hestia