On Thu, Nov 8, 2018 at 10:05 PM Jean Delvare <jdelvare@xxxxxxx> wrote: > > On Thu, 1 Nov 2018 16:27:07 +0100, Jean Delvare wrote: > > Hi David, > > > > The following commit: > > > > commit 7cf321d118a825c1541b43ca45294126fd474efa > > Author: Dave Airlie > > Date: Mon Oct 24 15:37:48 2016 +1000 > > > > drm/drivers: add support for using the arch wc mapping API. > > > > is causing a huge performance regression for the ast drm driver. In a > > text console, if I call "cat" on a large text file, it takes almost > > twice as much time to be displayed and scrolled completely. > > > > Can you please check that the ast driver portion of that commit is both > > correct and complete? > > And in the meantime, what bad will happen if we just revert the ast > portion of that commit? > This seems likely to be a hw problem with PCI writes to the AST "GPU", since it's just some sort of RAM + ARM on the end of a PCIE bus, we've definitely seen possible issues in the past with write combining around some of the mga GPUs with some CPUs. Have we seen the problem across a number of AST devices? Dave. _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
