Hi Nikolaus

Thanks for the detailed explanation.

Applied and pushed to drm-misc-next.

Sam

On Tue, Mar 10, 2020 at 08:43:19AM +0100, H. Nikolaus Schaller wrote:

The currently listed dotclock disagrees with the currently listed vrefresh rate. Change the dotclock to match the vrefresh.

There are two variants of the COM37H3M panel. The older one's COM37H3M05DTC data sheet specifies:

                     MIN      TYP     MAX

CLK frequency fCLK -- 22.4 26.3 MHz (in VGA mode) VSYNC Frequency fVSYNC 54 60 66 Hz VSYNC cycle time tv -- 650 -- H HSYNC frequency fHSYNC -- 39.3 -- kHz HSYNC cycle time th -- 570 -- CLK

The newer one's COM37H3M99DTC data sheet says:

                     MIN      TYP     MAX

CLK frequency fCLK 18 19.8 27 MHz VSYNC Frequency fVSYNC 54 60 66 Hz VSYNC cycle time tv 646 650 700 H HSYNC frequency fHSYNC -- 39.0 50.0 kHz HSYNC cycle time th 504 508 630 CLK

So we choose a parameter set that lies within the specs of both variants. We start at .vrefresh = 60, choose .htotal = 570 and .vtotal = 650 and end up in a clock of 22.230 MHz.

Reported-by: Ville Syrjala ville.syrjala@linux.intel.com Signed-off-by: H. Nikolaus Schaller hns@goldelico.com

---

drivers/gpu/drm/panel/panel-simple.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c index e14c14ac62b5..b4cb23d4898d 100644 --- a/drivers/gpu/drm/panel/panel-simple.c +++ b/drivers/gpu/drm/panel/panel-simple.c @@ -2390,15 +2390,15 @@ static const struct panel_desc ontat_yx700wv03 = { };

static const struct drm_display_mode ortustech_com37h3m_mode = {

• .clock = 22153,

• .clock = 22230, .hdisplay = 480,

• .hsync_start = 480 + 8,
• .hsync_end = 480 + 8 + 10,
• .htotal = 480 + 8 + 10 + 10,

• .hsync_start = 480 + 40,
• .hsync_end = 480 + 40 + 10,
• .htotal = 480 + 40 + 10 + 40, .vdisplay = 640, .vsync_start = 640 + 4,

• .vsync_end = 640 + 4 + 3,
• .vtotal = 640 + 4 + 3 + 4,

• .vsync_end = 640 + 4 + 2,
• .vtotal = 640 + 4 + 2 + 4, .vrefresh = 60, .flags = DRM_MODE_FLAG_NVSYNC | DRM_MODE_FLAG_NHSYNC,

};

2.23.0

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