On 18.11.2015 17:51, Daniel Vetter wrote: > On Wed, Nov 18, 2015 at 05:39:39PM +0900, Michel Dänzer wrote: >> On 18.11.2015 01:29, Daniel Vetter wrote: >>> >>> And no, I have absolutely no idea why radeon is pulling some tricks here, >>> which have been added in >>> >>> commit 78b1a6010b46a69bcd47b723a80f92693f26d17b >>> Author: Michel Dänzer <michel.daenzer@xxxxxxx> >>> Date: Tue Nov 18 18:00:08 2014 +0900 >>> >>> drm/radeon: Use cursor_set2 hook for enabling / disabling the HW cursor >>> >>> Michel/Alex, can you please shed some light onto this? >> >> As described in the rest of the commit log, the intention was to avoid >> the cursor intermittently appearing in the wrong location with existing >> userspace which sets the cursor BO in one ioctl call and the new >> position in another ioctl call. >> >> >>> radeon is the only driver doing this, making this interface inconsistent. >> >> It's only inconsistent in the case that userspace updates the cursor >> position to account for the new hotspot position in one ioctl call >> first, and only then sets the new BO in another ioctl call. In all other >> cases, the cursor position passed in by userspace is preserved. >> >> Anyway, in the meantime it has become apparent that this change didn't >> fully fix the problem, so feel free to revert it. > > Yeah I read the commit message but didn't understand what it's doing. > After some discussion with Alex on irc I realized that the fixup is only > applied in when updating the cursor bo and changing the hotspot to avoid > that kind of flickering. That problem is solved though on the kernel side > with universal planes (where we don't artificially split up the cursor > update into a move + bo-update for the driver interface any more). And > it's fixable in userspace even with legacy cursor interfaces since the > ioctl allows you to move + update at the same time too. It's just that X > doesn't provide that interface to the driver in a useful way. Well, the legacy cursor interfaces currently don't allow the driver to prevent the hardware from updating the cursor between the cursor_set / cursor_move calls. Anyway, I tried adding a cursor_lock hook for that purpose and adapting userspace accordingly, but it still doesn't seem to fully fix the problem. So I'm leaving it to somebody else / another day. :) -- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
