Re: omapfb: help from userspace

["Nathan Monson" <nmonson@gmail.com>]

On Thu, Oct 9, 2008 at 5:43 AM, Tony Lindgren <tony@atomide.com> wrote:
> Nathan, good to hear that the SO mode helps. But since you seem to
> have it easily reproducable..

Reproducing is as easy as applying the DSP Bridge kernel patches and
then running the 'ping.out' sample like this:  while true; do
ping.out; done

> Could you try the following patch based on RMK's earlier patch
> without the strongly ordered patch and see if that makes any
> difference?

Maybe it lasted a few seconds longer, or maybe it was luck, but in any
case it eventually went into an IRQ -33 loop even with this patch.

> If this patch alone does not do anything, maybe try reading back
> something from the dsp interrupt registers after write also
> in the dsp interrupt handler?

I will look into this and let you know.

> Also you might want to read through the thread linked in the
> patch description.
>
> And, if that still does not work, I'm suspecting that in some cases
> write-read is not enough, and only write-write ensures that it gets
> posted. Some ARM docs say that writes are only posted relative to
> other writes, but I don't know if it can be really that way.

Should I change the patch you sent me to do write write?

> At least we have at least one hack like that in the
> drivers/mmc/host/omap.c.
>
> Anyways, it would be nice to solve this issue for good. The problem
> has been making it easily reproducable.

At least I have a workaround for now.  It's good to be able to get DSP
work done.

- Nathan