On Mon, Jan 19, 2015 at 11:04:04AM +0000, Chris Wilson wrote: > On Mon, Jan 19, 2015 at 11:51:43AM +0100, Daniel Vetter wrote: > > There's also an issue in (most) X drivers which exaberates this > > issues: When changing the cursor buffer the X cursor code does a a) > > disable cursor b) update cursor image c) enable cursor cycle. > > Notably not -intel on which the bug has been observed. And more > importantly, the slow downs don't seem to correlate with cursor change, > just cursor movement. > -Chris > > -- > Chris Wilson, Intel Open Source Technology Centre
It seems that the simple fix for this case (movement only) is to just skip the prepare_fb/cleanup_fb calls (and the associated vblank wait) in the transitional plane helper when newfb == oldfb. I just posted a small patch that makes that change (and solves the cursor lag for me). This won't solve the case if userspace uses a different framebuffer for each update (while trying to update faster than the refresh rate). Is there any existing userspace that behaves this way that we can test with? Matt -- Matt Roper Graphics Software Engineer IoTG Platform Enabling & Development Intel Corporation (916) 356-2795 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
