Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
Pre-existing issues: - [High] Missing completion reinitialization causes spurious AUX transfer successes - [High] HPD event state overwrite race drops hotplug events -- --- Patch [4]: [PATCH v11 04/21] drm/bridge: synopsys: dw-dp: Document missing reset line deassert --- commit 34c619c6d4754597f7c81d207e5acfe482e8b36d Author: Sebastian Reichel <[email protected]> drm/bridge: synopsys: dw-dp: Document missing reset line deassert This patch adds a comment explaining why the driver avoids using automatically deasserting reset controls. Unbinding the device with the reset line deasserted can cause the SoC to hang if the shared power-domain is still active. The current reset handling remains unchanged. > diff --git a/drivers/gpu/drm/bridge/synopsys/dw-dp.c > b/drivers/gpu/drm/bridge/synopsys/dw-dp.c > index 21d60e89126f0..52e3b37259a69 100644 > --- a/drivers/gpu/drm/bridge/synopsys/dw-dp.c > +++ b/drivers/gpu/drm/bridge/synopsys/dw-dp.c [ ... ] [Severity: High] This isn't a bug introduced by this patch, but does dw_dp_aux_transfer() miss a completion reinitialization? drivers/gpu/drm/bridge/synopsys/dw-dp.c:dw_dp_aux_transfer() { ... regmap_write(dp->regmap, DW_DP_AUX_CMD, value); status = wait_for_completion_timeout(&dp->complete, timeout); ... } If a previous AUX transfer times out, wait_for_completion_timeout() returns 0 without decrementing the completion's done counter. If the hardware later generates an interrupt, the IRQ handler calls complete(&dp->complete). Will the next call to dw_dp_aux_transfer() immediately pass its wait_for_completion_timeout() without actually waiting for the new command to complete? This could lead to reading stale or invalid hardware status. [Severity: High] This is a pre-existing issue, but is there a hotplug event state overwrite race between dw_dp_handle_hpd_event() and dw_dp_hpd_work()? drivers/gpu/drm/bridge/synopsys/dw-dp.c:dw_dp_handle_hpd_event() { ... if (value & HPD_IRQ) { dev_dbg(dp->dev, "IRQ from the HPD\n"); dp->hotplug.long_hpd = false; regmap_write(dp->regmap, DW_DP_HPD_STATUS, HPD_IRQ); } if (value & HPD_HOT_PLUG) { dev_dbg(dp->dev, "Hot plug detected\n"); dp->hotplug.long_hpd = true; regmap_write(dp->regmap, DW_DP_HPD_STATUS, HPD_HOT_PLUG); } ... } If a long HPD event occurs, long_hpd is set to true and work is scheduled. If a short HPD event occurs before the workqueue runs, the interrupt handler overwrites long_hpd to false and calls schedule_work(), which coalesces with the pending work. drivers/gpu/drm/bridge/synopsys/dw-dp.c:dw_dp_hpd_work() { ... if (!long_hpd) { if (dw_dp_needs_link_retrain(dp)) { ret = dw_dp_link_retrain(dp); if (ret) dev_warn(dp->dev, "Retrain link failed\n"); } } else { drm_helper_hpd_irq_event(dp->bridge.dev); } ... } When the work finally executes, it sees long_hpd == false and fails to call drm_helper_hpd_irq_event(). Can this drop hotplug events, leaving userspace unaware of display connections? -- Sashiko AI review ยท https://sashiko.dev/#/patchset/20260806-synopsys-dw-dp-improvements-v11-0-0d508505f...@collabora.com?part=4
