[Cbe-oss-dev] [PATCH] spufs: avoid using backing operation for wbox write

[Christoph Hellwig]

On Fri, Aug 03, 2007 at 06:25:20PM -0300, Andre Detsch wrote:
> Subject: spufs: avoid using backing operation for wbox write
> 
> From: Andre Detsch <adetsch at br.ibm.com>
> 
> This patch disables the use of a backing operation for the execution
> of a write on context's mailbox while is it not bound to a SPU.
> The backing operation was consistently failing. Although the mailbox
> information was correctly being restored to the SPU when the ctx was
> rescheduled to run, SPU was not processing the data (keeping the SPU
> task blocked on the MB read operation), most likely because of the
> state of the internal event masks, some of them not writable from the
> PPU-side.
> With this patch, a mb write operation on a non-scheduled ctx is either
> blocked until the ctx gets scheduled (if !O_NONBLOCK), or returns
> EAGAIN (if O_NONBLOCK).

This fixes the problem for me on a QS20 blade, but on the simulator
it still hangs.