From: Claude Code Review Bot <claude-review@example.com>
To: dri-devel-reviews@example.com
Subject: Claude review: drm/msm/dpu: fix video mode DSC INTF timing width calculation
Date: Sun, 22 Mar 2026 04:21:57 +1000 [thread overview]
Message-ID: <review-patch4-20260319-dsi-rgb101010-support-v3-4-85b99df2d090@pm.me> (raw)
In-Reply-To: <20260319-dsi-rgb101010-support-v3-4-85b99df2d090@pm.me>
Patch Review
**This is the most interesting patch and the fix looks correct.**
The old code:
```c
timing->width = timing->width * drm_dsc_get_bpp_int(dsc) /
(dsc->bits_per_component * 3);
```
For 8-bit panels: `8 * 3 = 24` — works correctly.
For 10-bit panels: `10 * 3 = 30` — produces the wrong divisor, causing FIFO errors.
The fix:
```c
timing->width = timing->width * drm_dsc_get_bpp_int(dsc) / 24;
```
The reasoning is that DSI always transfers 24 bits of compressed data per pixel clock, regardless of source pixel depth. The compression ratio is already captured by `drm_dsc_get_bpp_int(dsc)` — the divisor represents the interface transfer width, not the source bit depth.
**This should have a `Fixes:` tag** since it fixes commit that originally added this DSC timing calculation. Without it, stable backport won't pick this up. The commit that introduced this formula should be identified and referenced.
The updated comment is clearer than the original:
```c
+ * For DSI, if DSC is enabled, 24 bits of compressed data are
+ * transferred per pclk regardless of the source pixel depth.
```
This is a real bug fix that would affect any non-8bpc DSC panel, independent of the RGB101010 format support.
---
Generated by Claude Code Patch Reviewer
next prev parent reply other threads:[~2026-03-21 18:21 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-19 11:57 [PATCH v3 0/4] drm/msm: add RGB101010 pixel format and fix 10-bit DSC timing Alexander Koskovich
2026-03-19 11:57 ` [PATCH v3 1/4] drm/msm/dsi: rename MSM8998 DSI version from V2_2_0 to V2_0_0 Alexander Koskovich
2026-03-19 12:05 ` Konrad Dybcio
2026-03-19 18:50 ` Dmitry Baryshkov
2026-03-21 18:21 ` Claude review: " Claude Code Review Bot
2026-03-19 11:57 ` [PATCH v3 2/4] drm/msm/dsi: add DSI version >= comparison helper Alexander Koskovich
2026-03-19 12:08 ` Konrad Dybcio
2026-03-19 18:50 ` Dmitry Baryshkov
2026-03-19 18:54 ` Dmitry Baryshkov
2026-03-21 18:21 ` Claude review: " Claude Code Review Bot
2026-03-19 11:57 ` [PATCH v3 3/4] drm/msm/dsi: Add support for RGB101010 pixel format Alexander Koskovich
2026-03-19 12:12 ` Konrad Dybcio
2026-03-19 18:59 ` Dmitry Baryshkov
2026-03-19 19:03 ` Alexander Koskovich
2026-03-20 9:22 ` kernel test robot
2026-03-20 17:58 ` kernel test robot
2026-03-21 18:21 ` Claude review: " Claude Code Review Bot
2026-03-19 11:58 ` [PATCH v3 4/4] drm/msm/dpu: fix video mode DSC INTF timing width calculation Alexander Koskovich
2026-03-19 14:09 ` Neil Armstrong
2026-03-19 14:40 ` Alexander Koskovich
2026-03-19 14:54 ` Neil Armstrong
2026-03-19 17:23 ` Jonathan Marek
2026-03-19 17:31 ` Alexander Koskovich
2026-03-19 19:02 ` Jonathan Marek
2026-03-20 1:45 ` Dmitry Baryshkov
2026-03-20 3:55 ` Alexander Koskovich
2026-03-20 4:25 ` Jonathan Marek
2026-03-20 4:46 ` Alexander Koskovich
2026-03-20 6:38 ` Dmitry Baryshkov
2026-03-20 6:50 ` Alexander Koskovich
2026-03-20 7:02 ` Alexander Koskovich
2026-03-20 7:36 ` Dmitry Baryshkov
2026-03-20 7:47 ` Alexander Koskovich
2026-03-20 8:17 ` Alexander Koskovich
2026-03-20 7:02 ` Dmitry Baryshkov
2026-03-20 7:34 ` Dmitry Baryshkov
2026-03-19 19:05 ` Dmitry Baryshkov
2026-03-21 18:21 ` Claude Code Review Bot [this message]
2026-03-21 18:21 ` Claude review: drm/msm: add RGB101010 pixel format and fix 10-bit DSC timing Claude Code Review Bot
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