Re: [PATCH] fb: do not ignore fb_set_par errors

[Florian Tobias Schandinat]

Andrew Morton schrieb:
> On Thu, 20 Aug 2009 11:59:56 +0000
> Florian Tobias Schandinat <FlorianSchandinat@xxxxxx> wrote:
>
> > at the moment about half of the framebuffer drivers can return an error
> > code in fb_set_par. Until now it would be silently ignored by fbmem.c
> > and fbcon.c. The following patch fixes fbmem.c to pass it on but I have
> > no idea what the right behaviour in fbcon.c would look like.
> > Any comments?
>
> Nobody really maintains this code any more and I don't know to whom
> your question should be addressed.  All I can suggest is that you
> decide what is the best path to take, and propose that we take it!  

Okay. I think it's difficult to ensure that we always end up with a 
working console. I assume that this is a very very rare case and as a 
start it should be enough to detect those cases and print an error message.

> Yes, it seems reasonable to me - if we ignore this the machine will
> probably crash later anyway.
>
> A well-behaved driver should leave the hardware in an unchanged state
> if it's going to return an error (IMO).
>
> Do you know of any bug reports which are due to this lack of checking?

No, I just hit the problem by thinking about how dynamic errors can be 
handled and looking at some drivers and fbmem.c.

> If you're concerned about the effects of this change, perhaps you
> should add a nice big printk when we decide to error out, so that it
> makes it easier for bug reporters (and responders!) to work out what
> happened?

That's a very good idea. Will add this too and resend the patch.


Thanks,

Florian Tobias Schandinat
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