Date: Thu, 30 Jun 2016 07:23:38 -0700 From: Maxim Sobolev <sobomax@freebsd.org> To: Ed Schouten <ed@nuxi.nl> Cc: Ernie Luzar <luzar722@gmail.com>, Kurt Jaeger <lists@opsec.eu>, =?UTF-8?Q?Trond_Endrest=C3=B8l?= <Trond.Endrestol@fagskolen.gjovik.no>, FreeBSD current <freebsd-current@freebsd.org> Subject: Re: console in 11.0-ALPHA4 Message-ID: <CAH7qZfs6s6UsbWtxJ1zqkAqU0eEdxmjDA79zxXJReHx3=k59Tg@mail.gmail.com> In-Reply-To: <CAH7qZfuoO-wQ0JNxCwqvJYdfHJC-FWz=1pWJVdk6vHRaEVX77w@mail.gmail.com> References: <57680D69.7030309@gmail.com> <alpine.BSF.2.20.1606201832250.1240@mail.fig.ol.no> <20160622090149.GD19494@home.opsec.eu> <576A74D0.2020704@gmail.com> <CAH7qZfuWdx9CAX-UJwJjh0u8HqCYFrUxDr3F9gbUoLo3Ss-bnQ@mail.gmail.com> <CABh_MKm8bxB_vFSw4Spcmt8ZA2htbEzXXEnkqcooowuPOifMzw@mail.gmail.com> <CAH7qZfuoO-wQ0JNxCwqvJYdfHJC-FWz=1pWJVdk6vHRaEVX77w@mail.gmail.com>
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P.S. Asynchronous nature of vt is also a poor excuse in my view. There are plenty ways to do it asynchronously, while preserving updates order. It should not be one-or-the-other deal. On Thu, Jun 30, 2016 at 7:21 AM, Maxim Sobolev <sobomax@freebsd.org> wrote: > Ed, I think this is bug, not a feature. People expect scrolling and > updates to be smooth these days, the fact that we deliberately break it > just signifies very weird preferences somebody made while developing the > code. The fact that it "looks fine when scrolling stops" is no execuse IMHO. > > -Max > > On Thu, Jun 30, 2016 at 6:42 AM, Ed Schouten <ed@nuxi.nl> wrote: > >> Hi Maxim, >> >> 2016-06-28 21:14 GMT+02:00 Maxim Sobolev <sobomax@freebsd.org>: >> > P.S. Just if somebody is interested in fixing those "fast scrolling text >> > turns into garbage" display issues, here is some screenshots of one of >> my >> > 11-alpha3 systems captured with a camera at 120fps. As you can see text >> > tears down quite badly. >> >> What happens is that rendering of vt(4) is done asynchronously. In >> addition to the screen contents, vt(4) keeps track of a rectangular >> area of the screen that needs to be updated. During every refresh, the >> rendering thread extracts and resets the coordinates of the >> rectangular area and redraws that area. It only holds a lock while >> extracting the rectangle's coordinates; not when redrawing. >> >> This means that if you have a lot of updates and redrawing is slow, >> you will get 'random' garbage on screen. Once output stops, the screen >> contents get refreshed one final time, making everything look all >> right again. >> >> -- >> Ed Schouten <ed@nuxi.nl> >> Nuxi, 's-Hertogenbosch, the Netherlands >> KvK-nr.: 62051717 >> >> >
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