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

[Arnd Bergmann]

On Sunday 05 August 2007, André Detsch wrote:
> When a context is restore to a SPU, 
> MFC_SPU_MAILBOX_WRITTEN_EVENT bit at SPU_WrEventAck may be 1, telling 
> the SPU not to process the MB event (mechanism used to avoid 
> re-processing of a same event). The bit is forced to 0 (internally in 
> the SPU) only when doing an out_be32(&prob->spu_mb_W, data), the direct 
> hw operation for writing to the SPU MB.

But the SPU_WrEventAck word _is_ written at the context restore time,
so we must have a way to give it a specific value. AFAICS, all that
needs to be done is to change the save channel data in
spu_state->chnldata[2] to restore the new correct value to 
SPU_WrEventAck through the channel access facility.

	Arnd <><