Re: X on 10.0 RC1 is unusable on my laptop

[tlaronde%kergis.com@localhost]

On Sat, Nov 25, 2023 at 03:44:05PM -0500, Greg Troxel wrote:
> Mike Pumford <mpumford%mudcovered.org.uk@localhost> writes:
> 
> > On 24/11/2023 16:28, Patrick Welche wrote:
> >> I notice that my artifacts (8th gen) disappear really quickly /
> >> hardly exist if the system is under load. Otherwise, they also self
> >> clear after about a second. Someone (tnn? rvp?) mentioned the
> >> possibility of cache lines not being flushed in this context.
> >> 
> > That matches my experience exactly. They completely disappear if the
> > system is under any sort of load. I'd always assumed it was a cache
> > thing and got exactly the same behaviour on 9-STABLE as well.
> 
> Do we think that the GPU reads from RAM separately from the CPU cache,
> so that bits written to a write-back cache are not in memory and thus
> not rendered correctly?  Is there some way to flush that cache after
> writing, or to set that region to write-through, or ?

There is one thing that is different with the memory: DRMKMS is the
only user of sys/uvm/pmap/pmap_pvt.c: pmap_pv_untrack().

Since, by nature, integrated GPUs are using directly the main memory,
it would perhaps be worth tracking this special usage---at least, it
shouldn't harm to start by that.
-- 
        Thierry Laronde <tlaronde +AT+ kergis +dot+ com>
                     http://www.kergis.com/
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