forked from Minki/linux
ebd0fd4bef
There are numerous places in the code where the driver's idea of how much space is left in a ring is updated using the driver's latest notions of the positions of 'head' and 'tail' for the ring. Among them are some that update one or both of these values before (re)doing the calculation. In particular, there are four different places in the code where 'last_retired_head' is copied to 'head' and then set to -1; and two of these do not have a guard to check that it has actually been updated since last time it was consumed, leaving the possibility that the dummy -1 can be transferred from 'last_retired_head' to 'head', causing the space calculation to produce 'impossible' results (previously seen on Android/VLV). This code therefore consolidates all the calculation and updating of these values, such that there is only one place where the ring space is updated, and it ALWAYS uses (and consumes) 'last_retired_head' if (and ONLY if) it has been updated since the last call. Signed-off-by: Dave Gordon <david.s.gordon@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> |
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| Makefile | ||