RE: [RFC][PATCH] omapfb: Condition mutex acquisition

Tomi Valkeinen
2009-09-29T14:53:32Z

On Tue, 2009-09-29 at 16:34 +0200, ext Aguirre Rodriguez, Sergio Alberto
wrote:
> From: Tomi Valkeinen [tomi.valkeinen@nokia.com]
> Sent: Tuesday, September 29, 2009 9:22 AM
> > On Tue, 2009-09-29 at 16:14 +0200, ext Aguirre Rodriguez, Sergio Alberto
> > wrote:
> > > From: Sergio Aguirre <saaguirre@ti.com>
> > >
> > > Acquiring mutex before framebuffer registration doesn't make sense,
> > > As there's no danger of external access to the memory related fields.
> >
> > What problem does this patch solve? It makes the code more complex.
> >
>
> Tomi,
>
> Thanks for your time.
>
> The problem was that, during platform driver registration,
> this sequence was executed:
>
> -> omapfb_probe
> -> omapfb_do_probe
> -> planes_init
> -> fbinfo_init
> -> set_fb_fix
> ...
> -> register_framebuffer
>
> And then, inside that function, an attempt of acquiring a
> mutex failed, because it wasn't initialized before trying it:
>
> mutex_lock(&fbi->mm_lock);
>
> It is actually initialized later in omapfb_do_probe in register_framebuffer call.
>
> So, how is the best to solve this then?

Oh, I wasn't implying that there's something wrong with the fix, I just
didn't know what it was fixing =).

Looks like a valid fix to me.

Tomi