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/driv...
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/cl...
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/ms...
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,