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@xxxxxxxxxxxxxxx>
> Signed-off-by: H. Nikolaus Schaller <hns@xxxxxxxxxxxxx>
> ---
> 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,
Numbers look consistent.
Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> .flags = DRM_MODE_FLAG_NVSYNC | DRM_MODE_FLAG_NHSYNC,
> };
> --
> 2.23.0
--
Ville Syrjälä
Intel
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