Re: simple framebuffer slower by factor of 20, on socfpga (arm) platform
flat view
From: Pavel Machek <hidden>
Date: 2015-04-24 13:31:33
Also in:
linux-devicetree, lkml
quoted
The difference is probably caused by memcpy() vs memcpy_fromio(). The comment above memcpy_fromio() says "This needs to be optimized". I think generally speaking memcpy_fromio() is correct for a framebuffer. 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...Could memcpy() cause alignment traps here if the fb pointer is unaligned and uncached?
Original commit did not comment on any failure, so I expect that is not a problem here... Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html