Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider: - [Medium] drm/imx: dc-crtc: missing dc_drv_set_crtc_disable() in dc_crtc_disable_at_boot() --
commit f302747895df5188605a9ca1ea0bd65af3b6d652 Author: Liu Ying <[email protected]> drm/imx: dc-crtc: Disable at boot This commit adds a helper dc_crtc_disable_at_boot() and calls it during dc_drm_bind() before drm_dev_register() to disable any running display controller pipes and balance clock enable counts after an unplug and rebind cycle. > diff --git a/drivers/gpu/drm/imx/dc/dc-crtc.c > b/drivers/gpu/drm/imx/dc/dc-crtc.c > index 0d64186a99018..c7dbe5f500b4a 100644 > --- a/drivers/gpu/drm/imx/dc/dc-crtc.c > +++ b/drivers/gpu/drm/imx/dc/dc-crtc.c > @@ -287,12 +288,24 @@ dc_crtc_atomic_enable(struct drm_crtc *crtc, struct > drm_atomic_commit *state) [ ... ] > @@ -318,8 +327,9 @@ dc_crtc_atomic_disable(struct drm_crtc *crtc, struct > drm_atomic_commit *state) > /* request display engine power-off when CRTC is disabled */ > pm_runtime_put(dc_crtc->de->dev); > > - drm_dev_exit(idx); > + dc_drv_set_crtc_disable(dc_drm, drm_crtc_index(crtc)); > > + drm_dev_exit(idx); > out: > drm_crtc_vblank_off(crtc); > > @@ -331,6 +341,43 @@ dc_crtc_atomic_disable(struct drm_crtc *crtc, struct > drm_atomic_commit *state) > spin_unlock_irq(&crtc->dev->event_lock); > } > > +void dc_crtc_disable_at_boot(struct drm_crtc *crtc) > +{ > + struct dc_drm_device *dc_drm = to_dc_drm_device(crtc->dev); > + struct dc_crtc *dc_crtc = to_dc_crtc(crtc); > + int ret; > + > + ret = pm_runtime_resume_and_get(dc_crtc->de->dev); > + if (ret < 0) { > + dc_crtc_err(crtc, "failed to get DC display engine RPM: %d\n", > + ret); > + return; > + } > + > + if (!dc_fg_wait_for_frame_index_moving(dc_crtc->fg)) { > + dc_crtc_dbg(crtc, "FrameGen frame index isn't moving\n"); > + goto out; > + } > + > + dc_crtc_dbg(crtc, "disabling FrameGen at boot\n"); > + __dc_crtc_disable_fg(crtc); > + > + if (!dc_drv_crtc_was_enabled(dc_drm, drm_crtc_index(crtc))) > + goto out; > + > + dc_crtc_dbg(crtc, "disabling clocks at boot\n"); > + > + dc_fg_disable_clock(dc_crtc->fg); > + > + if (!dc_drm->pe_clk_axi_disabled) { > + clk_disable_unprepare(dc_drm->pe->clk_axi); > + dc_drm->pe_clk_axi_disabled = true; > + } [Severity: Medium] Should dc_crtc_disable_at_boot() also call dc_drv_set_crtc_disable() after disabling the clocks here? When a pipe is enabled via dc_crtc_atomic_enable(), dc_drv_set_crtc_enable() sets the corresponding bit in priv->gp_regmap: drivers/gpu/drm/imx/dc/dc-drv.c:dc_drv_set_crtc_enable() { ... regmap_set_bits(priv->gp_regmap, 0, CRTC_ENABLED(crtc_index)); } If the device is then unplugged via dc_drm_unbind() -> drm_dev_unplug(), dc_crtc_atomic_disable() returns early at drm_dev_enter() without calling dc_drv_set_crtc_disable(). On the next bind in dc_drm_bind() -> dc_crtc_disable_at_boot(), the helper stops the frame generator, sees dc_drv_crtc_was_enabled() return true, and disables dc_crtc->fg->clk_disp and dc_drm->pe->clk_axi, dropping their clock enable and prepare counts back to zero. However, because it does not call dc_drv_set_crtc_disable(dc_drm, drm_crtc_index(crtc)), the enable bit in priv->gp_regmap remains set. If dc_crtc_disable_at_boot() runs again while the frame generator is active without an intervening atomic enable and disable cycle (for instance, across a warm reboot where the general-purpose register stays set and the bootloader enables the display, or if __dc_crtc_disable_fg() times out and bind is retried), wouldn't dc_drv_crtc_was_enabled() still see the stale bit and call dc_fg_disable_clock() and clk_disable_unprepare() on clocks that are already disabled? -- Sashiko AI review ยท https://sashiko.dev/#/patchset/[email protected]?part=6
