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.
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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