On Sun, Sep 08, 2024 at 11:50:30PM GMT, Linus Walleij wrote:
> The commit introducing the Frida display started to write the
> SETVCMOFF registers unconditionally, and some (not all!) Hydis
> display seem to be affected by ghosting after the commit.
>
> Make SETVCMOFF optional and only send these commands on the
> Frida display for now.
>
> Reported-by: Stefan Hansson <newbyte@xxxxxxxxxxxxxxxx>
> Fixes: 219a1f49094f ("drm/panel: nt35510: support FRIDA FRD400B25025-A-CTK")
> Acked-by: Jessica Zhang <quic_jesszhan@xxxxxxxxxxx>
> Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
> ---
> Changes in v2:
> - After Stefan's testing conclude that we only need to make
> SETVCMOFF optional.
> - Link to v1: https://lore.kernel.org/r/20240906-fix-nt35510-v1-1-1971f3af7dda@xxxxxxxxxx
> ---
> drivers/gpu/drm/panel/panel-novatek-nt35510.c | 18 ++++++++++++------
> 1 file changed, 12 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/panel/panel-novatek-nt35510.c b/drivers/gpu/drm/panel/panel-novatek-nt35510.c
> index d3bfdfc9cff6..a3460ed38cc4 100644
> --- a/drivers/gpu/drm/panel/panel-novatek-nt35510.c
> +++ b/drivers/gpu/drm/panel/panel-novatek-nt35510.c
> @@ -38,6 +38,7 @@
>
> #define NT35510_CMD_CORRECT_GAMMA BIT(0)
> #define NT35510_CMD_CONTROL_DISPLAY BIT(1)
> +#define NT35510_CMD_SETVCMOFF BIT(2)
>
> #define MCS_CMD_MAUCCTR 0xF0 /* Manufacturer command enable */
> #define MCS_CMD_READ_ID1 0xDA
> @@ -675,16 +676,19 @@ static int nt35510_setup_power(struct nt35510 *nt)
> nt->conf->bt2ctr);
> if (ret)
> return ret;
> +
> ret = nt35510_send_long(nt, dsi, NT35510_P1_SETVCL,
> NT35510_P1_VCL_LEN,
> nt->conf->vcl);
> if (ret)
> return ret;
> +
> ret = nt35510_send_long(nt, dsi, NT35510_P1_BT3CTR,
> NT35510_P1_BT3CTR_LEN,
> nt->conf->bt3ctr);
> if (ret)
> return ret;
> +
> ret = nt35510_send_long(nt, dsi, NT35510_P1_SETVGH,
> NT35510_P1_VGH_LEN,
> nt->conf->vgh);
I think this part is unrelted and should go in as a separate commit.
Other than that LGTM.
> @@ -721,11 +725,13 @@ static int nt35510_setup_power(struct nt35510 *nt)
> if (ret)
> return ret;
>
> - ret = nt35510_send_long(nt, dsi, NT35510_P1_SETVCMOFF,
> - NT35510_P1_VCMOFF_LEN,
> - nt->conf->vcmoff);
> - if (ret)
> - return ret;
> + if (nt->conf->cmds & NT35510_CMD_SETVCMOFF) {
> + ret = nt35510_send_long(nt, dsi, NT35510_P1_SETVCMOFF,
> + NT35510_P1_VCMOFF_LEN,
> + nt->conf->vcmoff);
> + if (ret)
> + return ret;
> + }
>
> /* Typically 10 ms */
> usleep_range(10000, 20000);
> @@ -1319,7 +1325,7 @@ static const struct nt35510_config nt35510_frida_frd400b25025 = {
> },
> .mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_BURST |
> MIPI_DSI_MODE_LPM,
> - .cmds = NT35510_CMD_CONTROL_DISPLAY,
> + .cmds = NT35510_CMD_CONTROL_DISPLAY | NT35510_CMD_SETVCMOFF,
> /* 0x03: AVDD = 6.2V */
> .avdd = { 0x03, 0x03, 0x03 },
> /* 0x46: PCK = 2 x Hsync, BTP = 2.5 x VDDB */
>
> ---
> base-commit: 8400291e289ee6b2bf9779ff1c83a291501f017b
> change-id: 20240906-fix-nt35510-a8ec6e47e036
>
> Best regards,
> --
> Linus Walleij <linus.walleij@xxxxxxxxxx>
>
--
With best wishes
Dmitry
