[PATCH v2 3/4] drm/msm/dsi: Allow values of 10 and 12 for bits per component

From: Danila Tikhonov
Date: Mon Feb 17 2025 - 17:26:01 EST


From: Eugene Lepshy <fekz115@xxxxxxxxx>

The DRM DSC helper has various bits_per_component values - not just 8.
But the DSC 1.1 block supports only 8, 10, and 12. Extend the guard
accordingly and add a comment noting this limitation.

Signed-off-by: Eugene Lepshy <fekz115@xxxxxxxxx>
Co-developed-by: Danila Tikhonov <danila@xxxxxxxxxxx>
Signed-off-by: Danila Tikhonov <danila@xxxxxxxxxxx>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
---
drivers/gpu/drm/msm/dsi/dsi_host.c | 18 +++++++++++++++---
1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index 007311c21fda..b9e247a23953 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -1767,8 +1767,20 @@ static int dsi_populate_dsc_params(struct msm_dsi_host *msm_host, struct drm_dsc
return -EINVAL;
}

- if (dsc->bits_per_component != 8) {
- DRM_DEV_ERROR(&msm_host->pdev->dev, "DSI does not support bits_per_component != 8 yet\n");
+ switch (dsc->bits_per_component) {
+ case 8:
+ case 10:
+ case 12:
+ /*
+ * Only 8, 10, and 12 bpc are supported for DSC 1.1 block.
+ * If additional bpc values need to be supported, update
+ * this quard with the appropriate DSC version verification.
+ */
+ break;
+ default:
+ DRM_DEV_ERROR(&msm_host->pdev->dev,
+ "Unsupported bits_per_component value: %d\n",
+ dsc->bits_per_component);
return -EOPNOTSUPP;
}

@@ -1779,7 +1791,7 @@ static int dsi_populate_dsc_params(struct msm_dsi_host *msm_host, struct drm_dsc
drm_dsc_set_const_params(dsc);
drm_dsc_set_rc_buf_thresh(dsc);

- /* handle only bpp = bpc = 8, pre-SCR panels */
+ /* DPU supports only pre-SCR panels */
ret = drm_dsc_setup_rc_params(dsc, DRM_DSC_1_1_PRE_SCR);
if (ret) {
DRM_DEV_ERROR(&msm_host->pdev->dev, "could not find DSC RC parameters\n");
--
2.48.1