On 06.07.2016 22:45, Tejun Heo wrote: > On Wed, Jul 06, 2016 at 12:12:52PM +0900, Michel Dänzer wrote: > >> Not being very familiar with the workqueue APIs, I'll describe how it's >> supposed to work from a driver POV, which will hopefully help you guys >> decide on the most appropriate alloc_workqueue parameters. >> >> There is one flip work queue for each hardware CRTC. At most one >> radeon_flip_work_func item can be queued for any of them at any time. >> When a radeon_flip_work_func item is queued, it should be executed ASAP >> (so WQ_HIGHPRI might be appropriate?). > > Hmmm... the only time WQ_HIGHPRI should be used is when it'd otherwise > require a kthread w/ nice value at -20. Would that be the case here? > What are the consequences of the work item getting delayed?
A page flip may be delayed to a later display refresh cycle. > Also, what kind of delays matter here? Is it millisec range or micro? It can be the latter in theory, but normally rather the former. -- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 181 bytes Desc: OpenPGP digital signature URL: <https://lists.freedesktop.org/archives/dri-devel/attachments/20160707/5178613d/attachment.sig>
