Hello Greg, On 1/19/22 12:47, Geert Uytterhoeven wrote: > On Wed, Jan 19, 2022 at 12:28 PM Greg Kroah-Hartman > <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: >> On Wed, Jan 19, 2022 at 12:22:55PM +0100, Greg Kroah-Hartman wrote: >>> On Wed, Jan 19, 2022 at 12:08:39PM +0100, Helge Deller wrote: >>>> This reverts commit 39aead8373b3c20bb5965c024dfb51a94e526151. >>>> >>>> Revert this patch. This patch started to introduce the regression that >>>> all hardware acceleration of more than 35 existing fbdev drivers were >>>> bypassed and thus fbcon console output for those was dramatically slowed >>>> down by factor of 10 and more. >>>> >>>> Reverting this commit has no impact on DRM, since none of the DRM drivers are >>>> tagged with the acceleration flags FBINFO_HWACCEL_COPYAREA, >>>> FBINFO_HWACCEL_FILLRECT or others. >>>> >>>> Signed-off-by: Helge Deller <deller@xxxxxx> > >>> As for "why", I think there was a number of private bugs that were >>> reported in this code, which is why it was removed. I do not think it >>> can be safely added back in without addressing them first. Let me go >>> dig through my email to see if I can find them... >> >> Ah, no, that was just the soft scrollback code I was thinking of, which Right. That was commit 973c096f6a85 and it was about vgacon, not fbcon. I did mentioned it in my cover letter, together with my analysis of the reported bugs. Maybe I should have put all the information from the cover letter into the patch here as well. If you haven't read the cover letter yet, please do. Helge > So the bugs argument is moot. > >> was a different revert and is still gone, thankfully :) > > FTR, not everyone else was thankful about that one... > >> This one was just removed because Daniel noticed that only 3 drivers >> used this (nouveau, omapdrm, and gma600), so this shouldn't have caused >> any regressions in any other drivers like you are reporting here. >> >> So perhaps this regression is caused by something else? > > 1. Daniel's patch was not CCed to linux-fbdev, > 2. When I discovered the patch, I pointed out that the premise of 3 > drivers was not true, and that it affects 32 more fbdev drivers[1] . > The patch was applied regardless. > 3. When the patch was suggested for backporting, I pointed out the > same[2]. > The patch was backported regardless. > > [1] https://lore.kernel.org/r/alpine.DEB.2.22.394.2010311116530.379363@xxxxxxxxxxxxxx/ > [2] https://lore.kernel.org/r/CAMuHMdXRgam2zahPEGcw8+76Xm-0AO-Ci9-YmVa5JpTKVHphRw@xxxxxxxxxxxxxx/ > > Gr{oetje,eeting}s, > > Geert
