On Thu, Mar 24, 2016 at 04:16:11PM -0300, Paulo Zanoni wrote: > FBC and the frontbuffer tracking infrastructure were designed assuming > that user space applications would follow a specific set of rules > regarding frontbuffer management and mmapping. I recently discovered > that current user space is not exactly following these rules: my > investigation led me to the conclusion that the generic backend from > SNA - used by SKL and the other new platforms without a specific > backend - is not issuing sw_finish/dirty_fb IOCTLs when using the CPU > and WC mmaps. I discovered this when running lightdm: I would type the > password and nothing would appear on the screen unless I moved the > mouse over the place where the letters were supposed to appear. Yes, that is a kernel bug. The protocol we said the kernel would follow is to disable FBC/WC when userspace marks the object for writing by the CPU and would only reestablish FBC/WC upon dirtyfb. -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx