forked from luck/tmp_suning_uos_patched
e517a5e970
Ever since we enabled GEM, the pre-9xx chipsets (particularly 865) have had serious stability issues. Back in May a wbinvd was added to the DRM to work around much of the problem. Some failure remained -- easily visible by dragging a window around on an X -retro desktop, or by looking at bugzilla. The chipset flush was on the right track -- hitting the right amount of memory, and it appears to be the only way to flush on these chipsets, but the flush page was mapped uncached. As a result, the writes trying to clear the writeback cache ended up bypassing the cache, and not flushing anything! The wbinvd would flush out other writeback data and often cause the data we wanted to get flushed, but not always. By removing the setting of the page to UC and instead just clflushing the data we write to try to flush it, we get the desired behavior with no wbinvd. This exports clflush_cache_range(), which was laying around and happened to basically match the code I was otherwise going to copy from the DRM. Signed-off-by: Eric Anholt <eric@anholt.net> Signed-off-by: Brice Goglin <Brice.Goglin@ens-lyon.org> Cc: stable@kernel.org |
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