On Mon, 6 Jul 2009 00:25:57 +0900 Paul Mundt <lethal@xxxxxxxxxxxx> 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 <lethal@xxxxxxxxxxxx> > > --- > 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.h1@xxxxx> 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.h1@xxxxx> --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
