Intel modesetting and tearing

[Greg V]

On Thu, Jan 10, 2019 at 9:40 PM, Johannes Lundberg <johalun0 at gmail.com> 
wrote:
> 
> 
> On Thu, Jan 10, 2019 at 18:35 Greg V <greg at unrelenting.technology> 
> wrote:
>> 
>> 
>>  On Thu, Jan 10, 2019 at 9:22 PM, Johannes Lundberg 
>> <johalun0 at gmail.com <mailto:johalun0 at gmail.com>>
>>  wrote:
>>  > On Thu, Jan 10, 2019 at 16:03 Christian Weisgerber
>>  > <naddy at mips.inka.de <mailto:naddy at mips.inka.de> 
>> <mailto:naddy at mips.inka.de <mailto:naddy at mips.inka.de>>>
>>  > wrote:
>>  >
>>  >> I recently switched from an obsolescent Radeon card to the 
>> built-in
>>  >> Intel HD Graphics P4600 with i915kms.ko and the modesetting 
>> driver.
>>  >> That works fine, but there is very noticeable tearing whenever
>>  >> something moves on-screen. If you google for it, you'll find 
>> plenty
>>  >> of complaints on Linux, so this is not a FreeBSD issue.
>>  >>
>>  >> For MPlayer, replacing the default Xvideo with GL video output 
>> (-vo
>>  >> gl)
>>  >> eliminates tearing.
>>  >>
>>  >> And as I found out just today and quite by accident, in Firefox
>>  >> toggling layers.acceleration.force-enabled to true will also
>>  >> eliminate
>>  >> all tearing, whether from soft-scrolling or when playing YouTube
>>  >> videos. Hallelujah!
>>  >
>>  >
>>  > Woot?! You mean I can use modesetting AND have tearfree Firefox?
>>  > Thanks for
>>  > the tip!! I will use this until I switch i3 -> Sway.
>> 
>>  When I still used X on my Intel laptop (of course with the 
>> modesetting
>>  DDX), I don't think GL acceleration of Firefox helped with tearing. 
>> (I
>>  always used GL accelerated Firefox anyway.)
>> 
>>  The solution was fiddling with compton flags, IIRC '--backend glx
>>  --vsync opengl-swc' was enough for the Intel GPU
> 
> What resolution? It’s less noticeable on smaller screens but on 
> 4K at 60Hz it’s quite severe and no Compton settings help. I tried 
> them all. Or maybe you mean Compton in combination GL in Firefox?

Yeah, I *always* used GL in Firefox.