[kmscon-devel] radeonsi scrambled graphics

[David Herrmann]

Hi

On Tue, Jan 21, 2014 at 7:34 PM, glphvgacs <darwinskernel at gmail.com> wrote:
> On Tue, Jan 21, 2014 at 07:22:08PM +0100, David Herrmann wrote:
>> Hi
>>
>> On Tue, Jan 21, 2014 at 7:16 PM, glphvgacs <darwinskernel at gmail.com> wrote:
>> > On Tue, Jan 21, 2014 at 07:12:21PM +0100, David Herrmann wrote:
>> >> Hi
>> >>
>> >> On Tue, Jan 21, 2014 at 7:08 PM, glphvgacs <darwinskernel at gmail.com> wrote:
>> >> > hello,
>> >> > scrambled is the best i could come up with for what i see, or not see
>> >> > really, when i pass --hwaccel --drm to kmscon. i'm including portions of
>> >> > the logs that are relavent but if you need more let me know.
>> >>
>> >> What happens if you don't pass --hwaccel?
>> >
>> > i works, but scrolling is *jittery*.
>>
>> Ugh, sure? That shouldn't happen. Can you run kmscon with --debug and
>> append the log?
>
> all the logs in my previous msg had --debug on.
>
>> And what exactly does "jittery" mean here? Does it not
>> update the screen atomically? Or does it lag? Or do you see artifacts?
>
> sorry, it's *tearing*. that is when i scroll down in vi or less i see
> tearing artifacts.

You always see tearing during fast-scrolls in terminals. vim has to
redraw the whole screen, so it sends all the 80x25 characters to the
TTY, but how does the TTY know at which point to redraw the console?
It doesn't, so you end up with tearing. But the tearing should be
glyph-wise, not pixel-wise as kmscon uses double-buffering.

Have you seen my comment regarding kmscube in the previous mail? Maybe
even the page-flipping is a radeonsi bug.

Thanks
David