On Mon, 6 Jul 2009 00:25:57 +0900
Paul Mundt <let...@linux-sh.org> 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 <let...@linux-sh.org>
>
> ---
>
This is incorrect way to fix this as some drivers do not use the
framebuffer_alloc()
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
fb_info
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 for
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)?
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.
Regards,
Krzysztof
From: Krzysztof Helt <krzysztof...@wp.pl>
Remove redundant call to the sisfb_get_fix() before sis frambuffer is
registered.
This fixes a problem with uninitialized the fb_info->mm_lock mutex.
Signed-off-by: Krzysztof Helt <krzysztof...@wp.pl>
---
diff -urp linux-ref/drivers/video/sis/sis_main.c
linux-next/drivers/video/sis/sis_main.c
--- linux-ref/drivers/video/sis/sis_main.c 2009-07-01 18:07:05.000000000
+0200
+++ linux-next/drivers/video/sis/sis_main.c 2009-07-05 17:20:33.000000000
+0200
@@ -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 +
ivideo->video_offset;
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
http://link.interia.pl/f222
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