Monday 10 August 2009 11:43:25 Janusz Krzysztofik wrote:
Monday 10 August 2009 10:50:06 Janusz Krzysztofik wrote:
Enhance period index accuracy, particularly just before buffer rewind, by making use of DMA interrupt status flags in addition to simply counting interrupts
Sorry, this one is still buggy
To be clear: I meant only patch 3/3 was buggy, others seemed OK.
an can break other OMAP models.
Overstatement.
The bug hits when multiple interrupt flags are set in parallel.
Under heavy debugging, for the first time I have noticed several consecutive DMA interrupt requests with all three flags set alltogether: FRAME, LAST and BLOCK. It looks hopeless, doesn't it? Keeping the period index at 0 will not report any progress, other choices (increment, set max) will lead to buffer loss, right?
Anyway, that observation seems to prove the requirement for a more accurate period counter. Improving it should help under heavy load. I think it is worth of trying, even if there may be other corner cases still not addressed.
v2 of the patch will follow next.
Janusz