On Thu, 29 Jan 2015 15:40:33 -0800 Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > On Wed, Jan 28, 2015 at 8:11 PM, Dave Airlie <airlied@xxxxxxxxxx> wrote: > > > > Linus, this came up a while back I finally got some confirmation > > that it fixes those servers. > > I'm certainly ok with this. which way should it go in? The users are: > > - drivers/tty/vt/vt.c (Greg KH, "tty layer") > > - drivers/video/console/* (fbcon people: Tomi Valkeinen and friends) > > and it might make sense to have *some* indication of how much worse > this makes fbcon performance in particular.. For devices that have no hardware scrolling it used to be double digit percentages difference between 32 and 64bit when reading from the fb because the reads are not posted and the latency killed you. Writes - not so big a deal - but the bridge should combine them anyway. I imagine 16bit read would be unprintably bad. Is it reads or writes that kill the card ? Also note that switching to lots of small writes may break the 3Dfx driver for the early 3Dfx PCI cards - they are really quite touchy about how they are fed. Unfortunately fbcon still matters for dumb EFI framebuffer fallbacks. vgacon it doesn't matter (if it was too slow you could make vgacon as fast as you want by only updating the off screen characters once per vertical blank). fbcon that is a bit harder as you are allowed to scribble on the display as well. You can't even check open/mmapped as you can open, scribble and close. Alan ------------------------------------------------------------------------------ Dive into the World of Parallel Programming. The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net/ -- _______________________________________________ Dri-devel mailing list Dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/dri-devel _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
