| Message ID | 20190505130413.32253-1-masneyb@onstation.org (mailing list archive) |
|---|---|
| Headers | show |
| Series | ARM: qcom: initial Nexus 5 display support | expand |
On Mon, May 06, 2019 at 08:42:36AM +0200, Linus Walleij wrote: > On Sun, May 5, 2019 at 3:04 PM Brian Masney <masneyb@onstation.org> wrote: > > > mdp5_get_scanoutpos() and mdp5_get_vblank_counter() both return 0, which > > is causing this stack trace to be dumped into the system log several > > times: > > > > WARNING: CPU: 0 PID: 5 at drivers/gpu/drm/drm_atomic_helper.c:1430 drm_atomic_helper_wait_for_vblanks.part.1+0x288/0x290 > > [CRTC:49:crtc-0] vblank wait timed out > > Modules linked in: > > CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 5.1.0-rc6-next-20190426-00006-g35c0d32a96e1-dirty #191 > > Hardware name: Generic DT based system > > Workqueue: events deferred_probe_work_func > > [<c031229c>] (unwind_backtrace) from [<c030d5ac>] (show_stack+0x10/0x14) > > [<c030d5ac>] (show_stack) from [<c0ac134c>] (dump_stack+0x78/0x8c) > > [<c0ac134c>] (dump_stack) from [<c0321660>] (__warn.part.3+0xb8/0xd4) > > [<c0321660>] (__warn.part.3) from [<c03216e0>] (warn_slowpath_fmt+0x64/0x88) > > [<c03216e0>] (warn_slowpath_fmt) from [<c0761a0c>] (drm_atomic_helper_wait_for_vblanks.part.1+0x288/0x290) > > [<c0761a0c>] (drm_atomic_helper_wait_for_vblanks.part.1) from [<c07b0a98>] (mdp5_complete_commit+0x14/0x40) > > [<c07b0a98>] (mdp5_complete_commit) from [<c07ddb80>] (msm_atomic_commit_tail+0xa8/0x140) > > [<c07ddb80>] (msm_atomic_commit_tail) from [<c0763304>] (commit_tail+0x40/0x6c) > > [<c07633f4>] (drm_atomic_helper_commit) from [<c07667f0>] (restore_fbdev_mode_atomic+0x168/0x1d4) > > I recently merged this patch: > https://cgit.freedesktop.org/drm/drm-misc/commit/?id=b3198c38f02d54a5e964258a2180d502abe6eaf0 > > I noticed that DSI is sometimes way slower than a monitor, even in HS mode. > On the MCDE this happened on the first screen update, which was slower > than 50ms. > > Check if your vblanks are simply slow, try bumping this timeout even higher, > I spent weeks finding this issue which boils down to an assumption that > the vblank will be fired from something like a monitor at 50 or 60 HZ > ~20 ms so 50ms seemed like a good timeout at the time. > > On a DSI display this is dubious, absolutely in LP mode, and even > in HS mode. That did not fix the issue for me, and I went as high as 5 seconds. That's good to know though since I would have likely ran into that same issue down the line. Brian
Here is a patch series that adds initial display support for the LG Nexus 5 (hammerhead) phone. The board 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: msm fd900000.mdss: pp done time out, lm=0 [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [CRTC:49:crtc-0] flip_done timed out [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [PLANE:32:plane-0] flip_done timed out mdp5_get_scanoutpos() and mdp5_get_vblank_counter() both return 0, which is causing this stack trace to be dumped into the system log several times: WARNING: CPU: 0 PID: 5 at drivers/gpu/drm/drm_atomic_helper.c:1430 drm_atomic_helper_wait_for_vblanks.part.1+0x288/0x290 [CRTC:49:crtc-0] vblank wait timed out Modules linked in: CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 5.1.0-rc6-next-20190426-00006-g35c0d32a96e1-dirty #191 Hardware name: Generic DT based system Workqueue: events deferred_probe_work_func [<c031229c>] (unwind_backtrace) from [<c030d5ac>] (show_stack+0x10/0x14) [<c030d5ac>] (show_stack) from [<c0ac134c>] (dump_stack+0x78/0x8c) [<c0ac134c>] (dump_stack) from [<c0321660>] (__warn.part.3+0xb8/0xd4) [<c0321660>] (__warn.part.3) from [<c03216e0>] (warn_slowpath_fmt+0x64/0x88) [<c03216e0>] (warn_slowpath_fmt) from [<c0761a0c>] (drm_atomic_helper_wait_for_vblanks.part.1+0x288/0x290) [<c0761a0c>] (drm_atomic_helper_wait_for_vblanks.part.1) from [<c07b0a98>] (mdp5_complete_commit+0x14/0x40) [<c07b0a98>] (mdp5_complete_commit) from [<c07ddb80>] (msm_atomic_commit_tail+0xa8/0x140) [<c07ddb80>] (msm_atomic_commit_tail) from [<c0763304>] (commit_tail+0x40/0x6c) [<c07633f4>] (drm_atomic_helper_commit) from [<c07667f0>] (restore_fbdev_mode_atomic+0x168/0x1d4) .... In mdp5_irq(), I see that a few vblank IRQ statuses (0x1000) come through when the board boots, drm_handle_vblank() is called, and the screen updates, however mdp5_get_scanoutpos() continues to return 0 after these operations complete. I don't see any ping-pong done IRQ statuses (0x100) come through in mdp5_irq(). I can get the text console to work with a 4.17 kernel with this patch https://patchwork.kernel.org/patch/10321845/ plus about a dozen or more other patches that have been mainlined since that release. The pp done and vblank messages still happen, however tty1 is updated when I write to it and Wayland works. The lg,acx467akm-7 panel listed below is currently handled by the simple panel driver since it is sufficient for 4.17 kernel, but that may need to change in the future for the power on commands. To be sure, I followed the instructions at https://github.com/freedreno/freedreno/wiki/DSI-Panel-Driver-Porting for porting the almost 400 panel on commands from the downstream kernel sources at https://github.com/AICP/kernel_lge_hammerhead/blob/n7.1/arch/arm/boot/dts/msm8974-hammerhead/msm8974-hammerhead-panel.dtsi#L645. The screen turns all white when the panel display is turned on and the panel exits sleep mode. Unfortunately, there are a lot of power on commands listed in the downstream device tree that aren't listed in mipi_display.h. Thanks in advance for any advice that you can provide. Brian Masney (6): drm/msm: fix null pointer dereference in msm_atomic_prepare_fb() drm/msm: add dirty framebuffer helper ARM: qcom_defconfig: add display-related options ARM: dts: msm8974: add display support ARM: dts: qcom: msm8974-hammerhead: add support for backlight ARM: dts: qcom: msm8974-hammerhead: add support for display .../qcom-msm8974-lge-nexus5-hammerhead.dts | 79 +++++++++++ arch/arm/boot/dts/qcom-msm8974.dtsi | 132 ++++++++++++++++++ arch/arm/configs/qcom_defconfig | 5 + drivers/gpu/drm/msm/msm_atomic.c | 8 +- drivers/gpu/drm/msm/msm_fb.c | 2 + 5 files changed, 223 insertions(+), 3 deletions(-)