Re: [PATCH 33/33] drm/panel-simple: Fix dotclock for LG ACX467AKM-7

Brian Masney
2020-03-05T08:15:32Z

On Tue, Mar 03, 2020 at 09:27:50PM -0500, Jonathan Marek wrote:
> modetest should be printing "freq: 60.0Hz", so definitely something wrong
> there. Though I guess you have another problem since I would expect the
> patch to drop it to 30 and not 13.5.

So I reverted the following three commits related to the async commit
support in the MSM driver:

d934a712c5e6 ("drm/msm: add atomic traces")
2d99ced787e3 ("drm/msm: async commit support")
194fc68d7a49 ("drm/msm/dpu: async commit support")

The modetest results now look much better:

# With existing 150000 clock rate on the panel
$ modetest -v -s 32:1080x19
setting mode 1080x1920-71.71Hz@XR24 on connectors 32, crtc 50
failed to set gamma: Function not implemented
freq: 59.40Hz
freq: 59.69Hz
freq: 59.69Hz
...

With Ville's patch the frequency drops slightly.

# With 125498 clock rate on the panel
$ modetest -v -s 32:1080x19
freq: 55.44Hz
freq: 55.09Hz
freq: 55.88Hz
...

Brian

>
> (FYI glmark-x11 isn't vsynced which is why I specifically mentioned
> glmark-drm)
>
> On 3/3/20 9:16 PM, Brian Masney wrote:
> > On Tue, Mar 03, 2020 at 08:04:05AM -0500, Jonathan Marek wrote:
> > > What Xorg prints doesn't mean anything. I don't think there will be errors
> > > in dmesg, you need to run something that does pageflips as fast as possible
> > > and see that the refresh rate is still 60. (modetest with -v, glmark-drm are
> > > examples)
> >
> > I assume that you mean modetest from
> > https://gitlab.freedesktop.org/mesa/drm/tree/master/tests/modetest ?
> > Here's the modeset connector information:
> >
> > id encoder status name size (mm) modes encoders
> > 32 31 connected DSI-1 62x110 1 31
> > modes:
> > index name refresh (Hz) hdisp hss hse htot vdisp vss vse vtot)
> > #0 1080x1920 71.71 1080 1082 1084 1086 1920 1922 1924 1926 150000
> > flags: ; type: preferred, driver
> >
> > And the page flip results...
> >
> > $ modetest -v -s 32:1080x1920
> > trying to open device 'msm'...done
> > setting mode 1080x1920-71.71Hz@XR24 on connectors 32, crtc 50
> > failed to set gamma: Function not implemented
> > freq: 13.50Hz
> > freq: 13.51Hz
> > freq: 13.51Hz
> >
> > It's the same results with and without Ville's patch.
> >
> > Here's the beginning of the glmark2 results with the x11-gl flavor:
> >
> > =======================================================
> > glmark2 2017.07
> > =======================================================
> > OpenGL Information
> > GL_VENDOR: freedreno
> > GL_RENDERER: FD330
> > GL_VERSION: 3.1 Mesa 20.0.0-devel
> > =======================================================
> > [build] use-vbo=false: FPS: 26 FrameTime: 38.462 ms
> > [build] use-vbo=true: FPS: 26 FrameTime: 38.462 ms
> > [texture] texture-filter=nearest: FPS: 26 FrameTime: 38.462 ms
> > [texture] texture-filter=linear: FPS: 26 FrameTime: 38.462 ms
> > [texture] texture-filter=mipmap: FPS: 27 FrameTime: 37.037 ms
> > [shading] shading=gouraud: FPS: 27 FrameTime: 37.037 ms
> > [shading] shading=blinn-phong-inf: FPS: 27 FrameTime: 37.037 ms
> > [shading] shading=phong: FPS: 27 FrameTime: 37.037 ms
> > [shading] shading=cel: FPS: 26 FrameTime: 38.462 ms
> > [bump] bump-render=high-poly: FPS: 27 FrameTime: 37.037 ms
> > [bump] bump-render=normals: FPS: 27 FrameTime: 37.037 ms
> > [bump] bump-render=height: FPS: 27 FrameTime: 37.037 ms
> > [effect2d] kernel=0,1,0;1,-4,1;0,1,0;: FPS: 25 FrameTime: 40.000 ms
> > [effect2d] kernel=1,1,1,1,1;1,1,1,1,1;1,1,1,1,1;: FPS: 26 FrameTime:
> > 38.462 ms
> > [pulsar] light=false:quads=5:texture=false: FPS: 26 FrameTime: 38.462 ms
> > [desktop] blur-radius=5:effect=blur:passes=1:separable=true:windows=4:
> > FPS: 26 FrameTime: 38.462 ms
> > [desktop] effect=shadow:windows=4: FPS: 27 FrameTime: 37.037 ms
> > ...
> >
> > Brian
> >
> >
> > >
> > > On 3/3/20 7:26 AM, Brian Masney wrote:
> > > > On Mon, Mar 02, 2020 at 10:36:54PM -0500, Jonathan Marek wrote:
> > > > > Another thing: did you verify that the panel still runs at 60hz (and not
> > > > > dropping frames to 30hz)? IIRC that was the behavior with lower clock.
> > > >
> > > > Yes, the panel is running at 60 HZ according to the Xorg log with
> > > > Ville's patch applied:
> > > >
> > > > modeset(0): Modeline "1080x1920"x60.0 125.50 1080 1082 1084 1086
> > > > 1920 1922 1924 1926 (115.6 kHz eP)
> > > >
> > > > I verified there's no underflow errors in dmesg.
> > > >
> > > > If I recall correctly, the clock speeds that was in your tree was set
> > > > too low for the gpu_opp_table (that wouldn't cause this issue), but I
> > > > seem to recall there were some other clock speed mismatches. The
> > > > bandwidth requests weren't set on the RPM as well, so maybe that
> > > > contributed to the problem. That's done upstream with the msm8974
> > > > interconnect driver:
> > > >
> > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/interconnect/qcom/msm8974.c
> > > >
> > > > There's a separate known issue with 'pp done time out' errors that
> > > > occur on the framebuffer that started upstream several months ago with
> > > > the introduction of async commit support in the MSM driver. I tried
> > > > working around this by enabling the autorefresh feature but it's not
> > > > fully working yet and I hit a dead end since there's no docs available
> > > > publicly for this. The grim details are at:
> > > >
> > > > https://lore.kernel.org/lkml/20191230020053.26016-2-masneyb@onstation.org/
> > > >
> > > > So I'm still OK with Ville's patch going in.
> > > >
> > > > Brian
> > > >
> > > >
> > > > >
> > > > > On 3/2/20 10:28 PM, Jonathan Marek wrote:
> > > > > >
> > > > > > On 3/2/20 10:13 PM, Brian Masney wrote:
> > > > > > > On Mon, Mar 02, 2020 at 03:48:22PM -0500, Jonathan Marek wrote:
> > > > > > > > Hi,
> > > > > > > >
> > > > > > > > This is a command mode panel and the the msm/mdp5 driver uses
> > > > > > > > the vrefresh
> > > > > > > > field for the actual refresh rate, while the dotclock field is
> > > > > > > > used for the
> > > > > > > > DSI clocks. The dotclock needed to be a bit higher than
> > > > > > > > necessary otherwise
> > > > > > > > the panel would not work.
> > > > > > > >
> > > > > > > > If you want to get rid of the separate clock/vrefresh fields there would
> > > > > > > > need to be some changes to msm driver.
> > > > > > > >
> > > > > > > > (note I hadn't made the patch with upstreaming in mind, the
> > > > > > > > 150000 value is
> > > > > > > > likely not optimal, just something that worked, this is something that
> > > > > > > > should have been checked with the downstream driver)
> > > > > > >
> > > > > > > Is this the right clock frequency in the downstream MSM 3.4 kernel that
> > > > > > > you're talking about?
> > > > > > >
> > > > > > > https://github.com/AICP/kernel_lge_hammerhead/blob/n7.1/arch/arm/mach-msm/clock-8974.c#L3326
> > > > > > >
> > > > > > >
> > > > > >
> > > > > > No, I'm talking about the DSI clock (the driver for it is in
> > > > > > drm/msm/dsi/). For a command mode panel the front/back porches aren't
> > > > > > relevant, but the dsi pixel/byte clock need to be a bit higher than
> > > > > > 1920x1080x60. Since 125498 is a little higher than 124416 that might be
> > > > > > enough (there is also rounding of the clock values to consider).
> > > > > >
> > > > > > > I don't see any obvious clock values in the downstream command mode
> > > > > > > panel configuration:
> > > > > > >
> > > > > > > https://github.com/AICP/kernel_lge_hammerhead/blob/n7.1/arch/arm/boot/dts/msm8974-hammerhead/msm8974-hammerhead-panel.dtsi#L591
> > > > > > >
> > > > > > >
> > > > > > > Anyways, I tried Ville's patch with the framebuffer, kmscube, and X11
> > > > > > > and everything appears to be working fine. You can add my Tested-by if
> > > > > > > you end up applying this.
> > > > > > >
> > > > > > > Tested-by: Brian Masney <masneyb@onstation.org>
> > > > > > >
> > > > > > > Brian
> > > > > > >
> > > > > > >
> > > > > > > > On 3/2/20 3:34 PM, Ville Syrjala wrote:
> > > > > > > > > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > > > > > > > >
> > > > > > > > > The currently listed dotclock disagrees with the currently
> > > > > > > > > listed vrefresh rate. Change the dotclock to match the vrefresh.
> > > > > > > > >
> > > > > > > > > Someone tell me which (if either) of the dotclock or vreresh is
> > > > > > > > > correct?
> > > > > > > > >
> > > > > > > > > Cc: Jonathan Marek <jonathan@marek.ca>
> > > > > > > > > Cc: Brian Masney <masneyb@onstation.org>
> > > > > > > > > Cc: Linus Walleij <linus.walleij@linaro.org>
> > > > > > > > > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > > > > > > > > ---
> > > > > > > > >    drivers/gpu/drm/panel/panel-simple.c | 2 +-
> > > > > > > > >    1 file changed, 1 insertion(+), 1 deletion(-)
> > > > > > > > >
> > > > > > > > > diff --git a/drivers/gpu/drm/panel/panel-simple.c
> > > > > > > > > b/drivers/gpu/drm/panel/panel-simple.c
> > > > > > > > > index b24fdf239440..f958d8dfd760 100644
> > > > > > > > > --- a/drivers/gpu/drm/panel/panel-simple.c
> > > > > > > > > +++ b/drivers/gpu/drm/panel/panel-simple.c
> > > > > > > > > @@ -3996,7 +3996,7 @@ static const struct panel_desc_dsi
> > > > > > > > > panasonic_vvx10f004b00 = {
> > > > > > > > >    };
> > > > > > > > >    static const struct drm_display_mode lg_acx467akm_7_mode = {
> > > > > > > > > -    .clock = 150000,
> > > > > > > > > +    .clock = 125498,
> > > > > > > > >        .hdisplay = 1080,
> > > > > > > > >        .hsync_start = 1080 + 2,
> > > > > > > > >        .hsync_end = 1080 + 2 + 2,
> > > > > > > > >