Hi Tzung-Bi, Thanks for the reviews. > From: Linux-mediatek <linux-mediatek-bounces@xxxxxxxxxxxxxxxxxxx> On > Behalf Of Tzung-Bi Shih > Sent: Thursday, November 18, 2021 1:55 PM > To: Jason-JH Lin (林睿祥) <Jason-JH.Lin@xxxxxxxxxxxx> > Cc: Chun-Kuang Hu <chunkuang.hu@xxxxxxxxxx>; Philipp Zabel < > p.zabel@xxxxxxxxxxxxxx>; Matthias Brugger <matthias.bgg@xxxxxxxxx>; > Jassi Brar <jassisinghbrar@xxxxxxxxx>; David Airlie <airlied@xxxxxxxx > >; Daniel Vetter <daniel@xxxxxxxx>; dri-devel@xxxxxxxxxxxxxxxxxxxxx; > linux-mediatek@xxxxxxxxxxxxxxxxxxx; > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > hsinyi@xxxxxxxxxxxx; fshao@xxxxxxxxxxxx; Nancy Lin (林欣螢) < > Nancy.Lin@xxxxxxxxxxxx>; Singo Chang (張興國) <Singo.Chang@xxxxxxxxxxxx> > Subject: Re: [PATCH 3/3] drm/mediatek: add devlink to cmdq dev > > On Wed, Nov 17, 2021 at 02:41:58PM +0800, jason-jh.lin wrote: > > @@ -158,6 +159,7 @@ static void mtk_drm_crtc_destroy(struct > > drm_crtc *crtc) > > mtk_drm_cmdq_pkt_destroy(&mtk_crtc->cmdq_handle); > > > > if (mtk_crtc->cmdq_client.chan) { > > + device_link_remove(mtk_crtc->drm_dev, mtk_crtc- > > >cmdq_client.chan->mbox->dev); > > mbox_free_channel(mtk_crtc->cmdq_client.chan); > > mtk_crtc->cmdq_client.chan = NULL; > > } > > [...] > > @@ -956,6 +959,16 @@ int mtk_drm_crtc_create(struct drm_device > > *drm_dev, > > } > > > > if (mtk_crtc->cmdq_client.chan) { > > + struct device_link *link; > > + > > + /* add devlink to cmdq dev to make sure suspend/resume > > order is correct */ > > + link = device_link_add(dev, mtk_crtc->cmdq_client.chan- > > >mbox->dev, > > + DL_FLAG_PM_RUNTIME | > > DL_FLAG_STATELESS); > > + if (!link) { > > + dev_err(dev, "Unable to link dev=%s\n", > > + dev_name(mtk_crtc->cmdq_client.chan- > > >mbox->dev)); > > + } > > + > > If device_link_add() failed, doesn't mtk_drm_crtc_create() need to > return an error and exit? OK, I'll add the return error at the next verion. > > OTOH, if device_link_add() failed, won't it bring any side effects to > call device_link_remove()? > Because device_link_remove() will find the device_link of supplier and consumer, then delete the device_link between them. If device_link_add() failed, supplier and consumer won't create the device_link. So calling device_link_remove() won't do anything without deive_link and won't bring any side effects. Regards, Jason-JH.Lin > _______________________________________________ > Linux-mediatek mailing list > Linux-mediatek@xxxxxxxxxxxxxxxxxxx > https://urldefense.com/v3/__http://lists.infradead.org/mailman/listinfo/linux-mediatek__;!!CTRNKA9wMg0ARbw!125dmOZ7xCLkwbIrzZf1VqVLQBbdT4RFHoMjR38U1GeCxaTM6xvvB-mSr7sTc6BuY5IH$ > -- Jason-JH Lin <jason-jh.lin@xxxxxxxxxxxx>