On 24/04/15 16:29, Pavel Machek wrote: > Hi! > > On Fri 2015-04-10 12:35:52, Archit Taneja wrote: >>> That said, if the fb is in RAM, and is only written by the CPU, I think >>> a normal memcpy() for fb_memcpy_fromfb() should be fine... >> >> I didn't test for performance regressions when I posted this patch. >> >> A look at _memcpy_fromio in arch/arm/kernel/io.c shows that readb() is used >> all the time, even when the source and destination addresses are aligned for >> larger reads to be possible. Other archs seem to use readl() or readq() when >> they can. Maybe that makes memcpy_fromio slower than the implementation of >> memcpy on arm? > > Ok, can you prepare a patch for me to try? Or should we just revert > the original commit? The old way worked fine, afaik, so maybe we can revert. But still, isn't it more correct to use memcpy_fromio? It's (possibly) io memory we have here. Tomi
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