On 11/12/11 17:10, Jassi Brar wrote: > On 11 December 2011 20:39, Javi Merino <javi.merino@xxxxxxx> wrote: >>>> >>>> What about properly tracking what we have sent to the DMA? Something >>>> like the following (warning *ugly* and untested code ahead, may eat your >>>> kitten): >>>> >>> Yeah, this is like I said 'marker' method. Though we can clean it up a bit. >>> 1) Pack req_running and lstenq together. Make lsteng return invalid value >>> should there be no buff programmed, otherwise 0 or 1. >> >> This can lead to starvation. If lstenq is -1 when the DMA hasn't been >> programmed yet, in _trigger() you don't know which buffer is the >> "oldest", so you may end up always starting the new buffer and >> forgetting about the other one. lstenq as it is right now prevents that. >> > Sorry I don't understand. If lstenq is -1 that means there's no req programmed > so trigger need not do anything. I didn't say we don't need to do anything else. Currently lstenq tracks the last request that pl330_submit_req() has enqueued. I think we should add a req_running (or any other name) that tracks what _trigger() has sent to the DMA. If we pack them together we lose some information and I don't see a way of packing them safely. > Though it's just an idea I haven't implemented and it may not work out. I was trying to implement it and got stuck in _trigger() thinking "ok, so which buffer am I supposed to trigger now..." > Just please give it a try if you can. Thanks. I have a patch that seems to be working. Let me test it a little bit more and I'll send it to the list. Cheers, Javi -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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