Hi Tomasz, Am Dienstag, den 24.11.2015, 17:27 +0900 schrieb Tomasz Figa: > Hi Philipp, CK, > > Please see my comments inline. Thank you for your comments. > On Thu, Nov 19, 2015 at 2:34 AM, Philipp Zabel <p.zabel@xxxxxxxxxxxxxx> wrote: > [snip] > > diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c > > new file mode 100644 > > index 0000000..508c8f3 > > --- /dev/null > > +++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c > > @@ -0,0 +1,596 @@ [...] > > +struct mtk_crtc_ddp_context; > > Is this forward declaration really necessary? Leftover, will remove. > > +/* > > + * MediaTek specific crtc structure. > > + * > > + * @base: crtc object. > > + * @pipe: a crtc index created at load() with a new crtc object creation > > + * and the crtc object would be set to private->crtc array > > + * to get a crtc object corresponding to this pipe from private->crtc > > + * array when irq interrupt occurred. the reason of using this pipe is that > > + * drm framework doesn't support multiple irq yet. > > + * we can refer to the crtc to current hardware interrupt occurred through > > + * this pipe value. > > Only first two fields documented? Also this isn't proper kerneldoc > syntax (see Documentation/kernel-doc-nano-HOWTO.txt). I'll fix that. > > + */ > > +struct mtk_drm_crtc { > > + struct drm_crtc base; > > + unsigned int pipe; > > + > > + bool do_flush; > > + > > + struct mtk_drm_plane planes[OVL_LAYER_NR]; > > + > > + void __iomem *config_regs; > > + struct mtk_disp_mutex *mutex; > > + u32 ddp_comp_nr; > > I assume this is size of ddp_comp array? Why not just unsigned int then? And that. > > + struct mtk_ddp_comp **ddp_comp; > > +}; > [snip] > > +static bool mtk_drm_crtc_mode_fixup(struct drm_crtc *crtc, > > + const struct drm_display_mode *mode, > > + struct drm_display_mode *adjusted_mode) > > +{ > > + /* drm framework doesn't check NULL */ > > Maybe rephrase the comment to "Nothing to do here, but the callback is > mandatory."? Ok. > > + return true; > > +} > [snip] > > +static void mtk_crtc_ddp_power_on(struct mtk_drm_crtc *mtk_crtc) > > +{ > > + int ret; > > + int i; > > + > > + DRM_INFO("mtk_crtc_ddp_power_on\n"); > > DRM_DEBUG_DRIVER() Yes, and the same for the following instances of this issue you point out below. > > + for (i = 0; i < mtk_crtc->ddp_comp_nr; i++) { > > + ret = clk_enable(mtk_crtc->ddp_comp[i]->clk); > > + if (ret) > > + DRM_ERROR("Failed to enable clock %d: %d\n", i, ret); > > This is unsafe, because even if we fail here, mtk_crtc_ddp_power_off() > will try to disable the clocks anyway, which will lead to negative > enable counts (and a WARN() in best case). Can we add proper error > handling to this function and other functions in the call stack? Ultimately these are called by the enable/disable drm_crtc_helper_funcs, which aren't allowed to fail. And clk_enable of core SoC clocks should never fail either. If we hit this error, something else is very wrong with the system already. I'll have mtk_crtc_ddp_power_on propagate the error and mtk_crtc_ddp_hw_init below bail out, and I'll also re-add the mtk_crtc->enabled bool again to let crtc_disable warn and bail out in case crtc_enable failed. [...] > > +static void mtk_crtc_ddp_hw_init(struct mtk_drm_crtc *mtk_crtc) > > +{ > > + struct drm_crtc *crtc = &mtk_crtc->base; > > + unsigned int width, height, vrefresh; > > + int ret; > > + int i; > > + > > + if (crtc->state) { > > + width = crtc->state->adjusted_mode.hdisplay; > > + height = crtc->state->adjusted_mode.vdisplay; > > + vrefresh = crtc->state->adjusted_mode.vrefresh; > > + } else { > > + WARN_ON(true); > > + width = 1920; > > + height = 1080; > > + vrefresh = 60; > > When can crtc->state be NULL? Also shouldn't we just fail here instead > of carrying on? > > + } > > nit: The if above can be replaced with the following. > > if (WARN_ON(!crtc->state)) { > // do the error handling > } else { > // dereference crtc->state > } > > This is better because the warning condition shows what's wrong. Ok. [...] > > + > > + /* disp_mtcmos */ I'll drop this comment. > > + ret = pm_runtime_get_sync(crtc->dev->dev); > > + if (ret < 0) > > + DRM_ERROR("Failed to enable power domain: %d\n", ret); > > Carrying on here after pm runtime error is at least inappropriate and > in practice is a good way to lock the system up... Ok, will be fixed as part of the error handling cleanup. [...] > > + mtk_crtc_ddp_power_off(mtk_crtc); > > + for (i = 0; i < mtk_crtc->ddp_comp_nr; i++) > > + mtk_disp_mutex_remove_comp(mtk_crtc->mutex, > > + mtk_crtc->ddp_comp[i]->id); > > + mtk_disp_mutex_disable(mtk_crtc->mutex); > > + for (i = 0; i < mtk_crtc->ddp_comp_nr - 1; i++) { > > + mtk_ddp_remove_comp_from_path(mtk_crtc->config_regs, > > + mtk_crtc->ddp_comp[i]->id, > > + mtk_crtc->ddp_comp[i + 1]->id); > > + mtk_disp_mutex_remove_comp(mtk_crtc->mutex, > > + mtk_crtc->ddp_comp[i]->id); > > + } > > + mtk_disp_mutex_remove_comp(mtk_crtc->mutex, mtk_crtc->ddp_comp[i]->id); > > + mtk_disp_mutex_unprepare(mtk_crtc->mutex); > > + mtk_crtc->mutex = NULL; > > mtk_crtc->mutex was acquired by mtk_disp_mutex_get(). Shouldn't it be > released with mtk_disp_mutex_put()? (In fact I can see > mtk_disp_ovl_unbind() already doing that). Absolutely yes, this was found really quickly. I missed it at first just because I forgot to plug in/out the HDMI connector a second time when testing. The NULL assignment needs to be removed here. > > + > > + /* disp_mtcmos */ > > This comment doesn't seem to be very meaningful. I'll drop it. > > + pm_runtime_put(drm->dev); > > +} > > To be continued. Thanks! regards Philipp -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html