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)
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@xxxxxxxxxxxxx/
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@xxxxxxxxxxxxx>
Brian
On 3/2/20 3:34 PM, Ville Syrjala wrote:
From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
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@xxxxxxxx>
Cc: Brian Masney <masneyb@xxxxxxxxxxxxx>
Cc: Linus Walleij <linus.walleij@xxxxxxxxxx>
Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
---
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,
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