On Fri, Dec 15, 2017 at 2:27 AM, Pekka Paalanen <ppaala...@gmail.com> wrote: > On Thu, 14 Dec 2017 10:11:32 -0500 > Alex Deucher <alexdeuc...@gmail.com> wrote: > >> On Thu, Dec 14, 2017 at 6:40 AM, Pekka Paalanen <ppaala...@gmail.com> wrote: >> > From: Pekka Paalanen <pekka.paala...@collabora.co.uk> >> > >> > Hi all, >> > >> > this is v5 (to match the numbering of my public branches) of the libweston >> > user >> > facing API and infrastructure for supporting shared-CRTC clone mode. >> > >> > Previous submission with rationale: >> > https://lists.freedesktop.org/archives/wayland-devel/2017-October/035604.html >> > >> > Design document: >> > https://phabricator.freedesktop.org/w/wayland/weston/atomic-output-config/ >> > >> > The goal: >> > https://phabricator.freedesktop.org/T7727 >> >> FWIW, at least with the DC modesetting code in amdgpu, we can >> synchronize multiple crtcs to the same timing when the monitors all >> support the same mode timing or with monitors that have different >> timings using variable length blanking periods on freesync capable >> monitors. > > Hi Alex, > > that's cool. How does userspace take advantage of that, how do you > configure KMS/atomic to make use of that? Is it supported through > legacy KMS (non-atomic) as well?
the driver automatically syncs all heads that it can at modeset time I think. > > Does it involve things like the driver stealing an unused CRTC for each > additional clone? No, there is logic in the gpu to sync the timing of multiple crtcs. You just need 1 crtc per display. > > The feature would fit perfectly under the "shared-CRTC clone mode" from > libweston API point of view, even though it's not actually a single > shared CRTC. > > > Thanks, > pq > >> >> >> Alex >> >> > >> > Changes in v5 compared to v3 are minor: >> > - "libweston: properly orphan wl_output resources" is new. >> > - Removal of wl_output global, when a head is detached from an enabled >> > output. >> > - Print "Detected a monitor change" only for enabled heads. >> > >> > You can find this series in the branch: >> > https://gitlab.collabora.com/pq/weston/commits/clonemode-user-API-5 >> > >> > I went through the same testing procedure as with v3, the previous >> > submission. >> > >> > >> > However, the interesting bits are in the branch: >> > https://gitlab.collabora.com/pq/weston/commits/clonemode-4 >> > >> > As new things compared to clonemode-user-API-2, that one contains: >> > - support for configuring clone mode in weston.ini >> > - main.c implementation to configure a clode using the new API >> > - desktop-shell enhancements to avoid redundant panel and background >> > surfaces >> > in clone mode >> > - hooking up custom data to weston_output via a new user-side destroy >> > signal >> > - naming outputs freely >> > - DRM-backend support for shared-CRTC clone mode >> > - video mode list merging in the DRM-backend >> > >> > The shared-CRTC clone mode has been tested to work on an i.MX6 device. >> > Unfortunately it seems that PC hardware that would support it is becoming >> > scarce AFAIU. >> > >> > Most of the patches in clonemode-4 depend on the atomic modesetting series >> > and >> > can therefore be submitted only after that one. >> > _______________________________________________ wayland-devel mailing list wayland-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/wayland-devel
