On Tue, May 28, 2019 at 07:32:14PM -0600, Jeffrey Hugo wrote: > On Tue, May 28, 2019 at 7:17 PM Brian Masney <masneyb@xxxxxxxxxxxxx> wrote: > > > > On Tue, May 28, 2019 at 03:46:14PM +0200, Linus Walleij wrote: > > > On Thu, May 9, 2019 at 4:04 AM Brian Masney <masneyb@xxxxxxxxxxxxx> wrote: > > > > > > > Here is a patch series that adds initial display support for the LG > > > > Nexus 5 (hammerhead) phone. It's not fully working so that's why some > > > > of these patches are RFC until we can get it fully working. > > > > > > > > The phones boots into terminal mode, however there is a several second > > > > (or more) delay when writing to tty1 compared to when the changes are > > > > actually shown on the screen. The following errors are in dmesg: > > > > > > I tested to apply patches 2-6 and got the console up on the phone as well. > > > I see the same timouts, and I also notice the update is slow in the > > > display, as if the DSI panel was running in low power (LP) mode. > > > > > > Was booting this to do some other work, but happy to see the progress! > > > > Thanks! > > > > I've had three people email me off list regarding the display working on > > 4.17 before the msm kms/drm driver was converted to the DRM atomic API so > > this email is to get some more information out publicly. > > > > I pushed up a branch to my github with 15 patches applied against 4.17 > > that has a working display: > > > > https://github.com/masneyb/linux/commits/display-works-4.17 > > > > It's in low speed mode but its usable. The first 10 patches are in > > mainline now and the last 5 are in essence this patch series with the > > exception of 'drm/atomic+msm: add helper to implement legacy dirtyfb'. > > There's a slightly different version of that patch in mainline now. > > > > I'm planning to work on the msm8974 interconnect support once some of > > the outstanding interconnect patches for the msm kms/drm driver arrive > > in mainline. I'd really like to understand why the display works on > > 4.17 with those patches though. I assume that it's related to the > > vblank events not working properly? Let me preface this with I'm a > > total DRM newbie, but it looked like the pre-DRM-atomic driver wasn't > > looking for these events in the atomic commits before the migration? > > See commit 70db18dca4e0 ("drm/msm: Remove msm_commit/worker, use atomic > > helper commit"), specifically the drm_atomic_helper_wait_for_vblanks() > > call that was added. > > Do you know if the nexus 5 has a video or command mode panel? There > is some glitchyness with vblanks and command mode panels. Its in command mode. I know this because I see two 'pp done time out' messages, even on 4.17. Based on my understanding, the ping pong code is only applicable for command mode panels. Brian
