[PATCH 2/4] drm/i915/vlv_dsi: Add DMI quirk for wrong I2C bus and panel size on Lenovo Yoga Tablet 2 series (v2)

[Jani Nikula]

On Sat, 16 Sep 2023, Hans de Goede <hdegoede at redhat.com> wrote:
> On the Lenovo Yoga Tablet 2 830 / 1050 there are 2 problems:
>
> 1. The I2C MIPI sequence elements reference bus 3. ACPI has I2C1 - I2C7
>    which under Linux become bus 0 - 6. And the MIPI sequence reference
>    to bus 3 is indented for I2C3 which is bus 2 under Linux.
>
>    This leads to errors like these:
>    [  178.244049] i2c_designware 80860F41:03: controller timed out
>    [  178.245703] i915 0000:00:02.0: [drm] *ERROR* Failed to xfer payload of size (1) to reg (169)
>    There are 3 timeouts when the panel is on, delaying
>    waking up the screen on a key press by 3 seconds.
>
>    Note mipi_exec_i2c() cannot just subtract 1 from the bus
>    given in the I2C MIPI sequence element. Since on other
>    devices the I2C bus-numbers used in the MIPI sequences do
>    actually start at 0.
>
> 2. width_/height_mm contain a bogus 192mm x 120mm size. This is
>    especially a problem on the 8" 830 version which uses a 10:16
>    portrait screen where as the bogus size is 16:10.
>
> Add a DMI quirk to override the I2C bus and the panel size with
> the correct values.
>
> Note both the 10" 1050 models as well as the 8" 830 models use the same
> mainboard and thus the same DMI strings. The 10" 1050 uses a 1920x1200
> landscape screen, where as the 8" 830 uses a 1200x1920 portrait screen,
> so the quirk handling uses the display resolution to detect the model.
>
> Changes in v2:
> - Also override i2c_bus_num to fix mipi_exec_i2c() timeouts
>
> Reviewed-by: Javier Martinez Canillas <javierm at redhat.com>
> Signed-off-by: Hans de Goede <hdegoede at redhat.com>
> ---
>  drivers/gpu/drm/i915/display/vlv_dsi.c | 50 ++++++++++++++++++++++++++
>  1 file changed, 50 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/vlv_dsi.c b/drivers/gpu/drm/i915/display/vlv_dsi.c
> index 51c4b1491fa2..e247e3413d90 100644
> --- a/drivers/gpu/drm/i915/display/vlv_dsi.c
> +++ b/drivers/gpu/drm/i915/display/vlv_dsi.c
> @@ -1765,6 +1765,42 @@ static void vlv_dsi_asus_tf103c_mode_fixup(struct intel_dsi *intel_dsi)
>  		fixed_mode->vtotal -= 4;
>  }
>  
> +/*
> + * On the Lenovo Yoga Tablet 2 830 / 1050 there are 2 problems:
> + * 1. The I2C MIPI sequence elements reference bus 3. ACPI has I2C1 - I2C7
> + *    which under Linux become bus 0 - 6. And the MIPI sequence reference
> + *    to bus 3 is indented for I2C3 which is bus 2 under Linux.
> + *
> + *    Note mipi_exec_i2c() cannot just subtract 1 from the bus
> + *    given in the I2C MIPI sequence element. Since on other
> + *    devices the I2C bus-numbers used in the MIPI sequences do
> + *    actually start at 0.
> + *
> + * 2. width_/height_mm contain a bogus 192mm x 120mm size. This is
> + *    especially a problem on the 8" 830 version which uses a 10:16
> + *    portrait screen where as the bogus size is 16:10.
> + */
> +static void vlv_dsi_lenovo_yoga_tab2_size_fixup(struct intel_dsi *intel_dsi)
> +{
> +	const struct drm_display_mode *fixed_mode =
> +		intel_panel_preferred_fixed_mode(intel_dsi->attached_connector);
> +	struct drm_display_info *info = &intel_dsi->attached_connector->base.display_info;
> +
> +	intel_dsi->i2c_bus_num = 2;
> +
> +	/*
> +	 * The 10" 1050 uses a 1920x1200 landscape screen, where as the 8" 830
> +	 * uses a 1200x1920 portrait screen.
> +	 */
> +	if (fixed_mode->hdisplay == 1920) {
> +		info->width_mm = 216;
> +		info->height_mm = 135;
> +	} else {
> +		info->width_mm = 107;
> +		info->height_mm = 171;
> +	}

Not a problem here it seems... but generally we should (at drm level)
separate display info originating from EDID (which will get erased at
display probe) and display info originating from other channels (which
should not be erased at display probe).

BR,
Jani.


> +}
> +
>  static const struct dmi_system_id vlv_dsi_dmi_quirk_table[] = {
>  	{
>  		/* Asus Transformer Pad TF103C */
> @@ -1774,6 +1810,20 @@ static const struct dmi_system_id vlv_dsi_dmi_quirk_table[] = {
>  		},
>  		.driver_data = (void *)vlv_dsi_asus_tf103c_mode_fixup,
>  	},
> +	{
> +		/*
> +		 * Lenovo Yoga Tablet 2 830F/L or 1050F/L (The 8" and 10"
> +		 * Lenovo Yoga Tablet 2 use the same mainboard)
> +		 */
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "Intel Corp."),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "VALLEYVIEW C0 PLATFORM"),
> +			DMI_MATCH(DMI_BOARD_NAME, "BYT-T FFD8"),
> +			/* Partial match on beginning of BIOS version */
> +			DMI_MATCH(DMI_BIOS_VERSION, "BLADE_21"),
> +		},
> +		.driver_data = (void *)vlv_dsi_lenovo_yoga_tab2_size_fixup,
> +	},
>  	{ }
>  };

-- 
Jani Nikula, Intel