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Message-ID: <ebdcae6ba331771e4bdba729d642d7178a10e8bc.camel@mediatek.com>
Date: Mon, 21 Mar 2022 15:10:38 +0800
From: Rex-BC Chen <rex-bc.chen@...iatek.com>
To: CK Hu <ck.hu@...iatek.com>, <chunkuang.hu@...nel.org>
CC: <airlied@...ux.ie>, <jason-jh.lin@...iatek.com>,
<linux-kernel@...r.kernel.org>, <dri-devel@...ts.freedesktop.org>,
<Project_Global_Chrome_Upstream_Group@...iatek.com>,
<nancy.lin@...iatek.com>, <linux-mediatek@...ts.infradead.org>,
<yongqiang.niu@...iatek.com>, <hsinyi@...gle.com>,
<matthias.bgg@...il.com>, <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH V1] drm/mediatek: Fix issue of vblank callback data is
NULL
On Mon, 2022-03-21 at 15:07 +0800, CK Hu wrote:
> Hi, Rex:
>
> I would like the title be WHAT does this patch do and the commit
> message be WHY does this patch do. I think what does this patch do is
> adding vblank register/unregister function.
>
> Regards,
> CK
>
Hello CK,
Ok, I will modify the title for this series in next version.
Thanks!
BRs,
Rex
> On Mon, 2022-03-21 at 13:53 +0800, Rex-BC Chen wrote:
> > We encountered a kernel panic issue that callback data will be NULL
> > when
> > it's using in ovl irq handler. There is a timing issue between
> > mtk_disp_ovl_irq_handler() and mtk_ovl_disable_vblank().
> >
> > To resolve this issue, we use the flow to register/unregister
> > vblank
> > cb:
> > - Register callback function and callback data when crtc creates.
> > - Unregister callback function and callback data when crtc
> > destroies.
> >
> > With this solution, we can assure callback data will not be NULL
> > when
> > vblank is disable.
> >
> > Fixes: 9b0704988b15 ("drm/mediatek: Register vblank callback
> > function")
> > Signed-off-by: Rex-BC Chen <rex-bc.chen@...iatek.com>
> > Reviewed-by: jason-jh.lin <jason-jh.lin@...iatek.com>
> > ---
> > drivers/gpu/drm/mediatek/mtk_disp_drv.h | 16 +++++++-----
> > drivers/gpu/drm/mediatek/mtk_disp_ovl.c | 22 ++++++++++++----
> > drivers/gpu/drm/mediatek/mtk_disp_rdma.c | 20 +++++++++-----
> > drivers/gpu/drm/mediatek/mtk_drm_crtc.c | 14 +++++++++-
> > drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c | 4 +++
> > drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h | 29 ++++++++++++++++-
> > --
> > --
> > 6 files changed, 80 insertions(+), 25 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/mediatek/mtk_disp_drv.h
> > b/drivers/gpu/drm/mediatek/mtk_disp_drv.h
> > index 86c3068894b1..974462831133 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_disp_drv.h
> > +++ b/drivers/gpu/drm/mediatek/mtk_disp_drv.h
> > @@ -76,9 +76,11 @@ void mtk_ovl_layer_off(struct device *dev,
> > unsigned int idx,
> > void mtk_ovl_start(struct device *dev);
> > void mtk_ovl_stop(struct device *dev);
> > unsigned int mtk_ovl_supported_rotations(struct device *dev);
> > -void mtk_ovl_enable_vblank(struct device *dev,
> > - void (*vblank_cb)(void *),
> > - void *vblank_cb_data);
> > +void mtk_ovl_register_vblank_cb(struct device *dev,
> > + void (*vblank_cb)(void *),
> > + void *vblank_cb_data);
> > +void mtk_ovl_unregister_vblank_cb(struct device *dev);
> > +void mtk_ovl_enable_vblank(struct device *dev);
> > void mtk_ovl_disable_vblank(struct device *dev);
> >
> > void mtk_rdma_bypass_shadow(struct device *dev);
> > @@ -93,9 +95,11 @@ void mtk_rdma_layer_config(struct device *dev,
> > unsigned int idx,
> > struct cmdq_pkt *cmdq_pkt);
> > void mtk_rdma_start(struct device *dev);
> > void mtk_rdma_stop(struct device *dev);
> > -void mtk_rdma_enable_vblank(struct device *dev,
> > - void (*vblank_cb)(void *),
> > - void *vblank_cb_data);
> > +void mtk_rdma_register_vblank_cb(struct device *dev,
> > + void (*vblank_cb)(void *),
> > + void *vblank_cb_data);
> > +void mtk_rdma_unregister_vblank_cb(struct device *dev);
> > +void mtk_rdma_enable_vblank(struct device *dev);
> > void mtk_rdma_disable_vblank(struct device *dev);
> >
> > #endif
> > diff --git a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
> > b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
> > index 2146299e5f52..1fa1bbac9f9c 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
> > @@ -96,14 +96,28 @@ static irqreturn_t mtk_disp_ovl_irq_handler(int
> > irq, void *dev_id)
> > return IRQ_HANDLED;
> > }
> >
> > -void mtk_ovl_enable_vblank(struct device *dev,
> > - void (*vblank_cb)(void *),
> > - void *vblank_cb_data)
> > +void mtk_ovl_register_vblank_cb(struct device *dev,
> > + void (*vblank_cb)(void *),
> > + void *vblank_cb_data)
> > {
> > struct mtk_disp_ovl *ovl = dev_get_drvdata(dev);
> >
> > ovl->vblank_cb = vblank_cb;
> > ovl->vblank_cb_data = vblank_cb_data;
> > +}
> > +
> > +void mtk_ovl_unregister_vblank_cb(struct device *dev)
> > +{
> > + struct mtk_disp_ovl *ovl = dev_get_drvdata(dev);
> > +
> > + ovl->vblank_cb = NULL;
> > + ovl->vblank_cb_data = NULL;
> > +}
> > +
> > +void mtk_ovl_enable_vblank(struct device *dev)
> > +{
> > + struct mtk_disp_ovl *ovl = dev_get_drvdata(dev);
> > +
> > writel(0x0, ovl->regs + DISP_REG_OVL_INTSTA);
> > writel_relaxed(OVL_FME_CPL_INT, ovl->regs +
> > DISP_REG_OVL_INTEN);
> > }
> > @@ -112,8 +126,6 @@ void mtk_ovl_disable_vblank(struct device *dev)
> > {
> > struct mtk_disp_ovl *ovl = dev_get_drvdata(dev);
> >
> > - ovl->vblank_cb = NULL;
> > - ovl->vblank_cb_data = NULL;
> > writel_relaxed(0x0, ovl->regs + DISP_REG_OVL_INTEN);
> > }
> >
> > diff --git a/drivers/gpu/drm/mediatek/mtk_disp_rdma.c
> > b/drivers/gpu/drm/mediatek/mtk_disp_rdma.c
> > index d41a3970b944..943780fc7bf6 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_disp_rdma.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_disp_rdma.c
> > @@ -94,24 +94,32 @@ static void rdma_update_bits(struct device
> > *dev,
> > unsigned int reg,
> > writel(tmp, rdma->regs + reg);
> > }
> >
> > -void mtk_rdma_enable_vblank(struct device *dev,
> > - void (*vblank_cb)(void *),
> > - void *vblank_cb_data)
> > +void mtk_rdma_register_vblank_cb(struct device *dev,
> > + void (*vblank_cb)(void *),
> > + void *vblank_cb_data)
> > {
> > struct mtk_disp_rdma *rdma = dev_get_drvdata(dev);
> >
> > rdma->vblank_cb = vblank_cb;
> > rdma->vblank_cb_data = vblank_cb_data;
> > - rdma_update_bits(dev, DISP_REG_RDMA_INT_ENABLE,
> > RDMA_FRAME_END_INT,
> > - RDMA_FRAME_END_INT);
> > }
> >
> > -void mtk_rdma_disable_vblank(struct device *dev)
> > +void mtk_rdma_unregister_vblank_cb(struct device *dev)
> > {
> > struct mtk_disp_rdma *rdma = dev_get_drvdata(dev);
> >
> > rdma->vblank_cb = NULL;
> > rdma->vblank_cb_data = NULL;
> > +}
> > +
> > +void mtk_rdma_enable_vblank(struct device *dev)
> > +{
> > + rdma_update_bits(dev, DISP_REG_RDMA_INT_ENABLE,
> > RDMA_FRAME_END_INT,
> > + RDMA_FRAME_END_INT);
> > +}
> > +
> > +void mtk_rdma_disable_vblank(struct device *dev)
> > +{
> > rdma_update_bits(dev, DISP_REG_RDMA_INT_ENABLE,
> > RDMA_FRAME_END_INT, 0);
> > }
> >
> > diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> > b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> > index d661edf7e0fe..e42a9bfa0ecb 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> > @@ -152,6 +152,7 @@ static void mtk_drm_cmdq_pkt_destroy(struct
> > cmdq_pkt *pkt)
> > static void mtk_drm_crtc_destroy(struct drm_crtc *crtc)
> > {
> > struct mtk_drm_crtc *mtk_crtc = to_mtk_crtc(crtc);
> > + int i;
> >
> > mtk_mutex_put(mtk_crtc->mutex);
> > #if IS_REACHABLE(CONFIG_MTK_CMDQ)
> > @@ -162,6 +163,14 @@ static void mtk_drm_crtc_destroy(struct
> > drm_crtc
> > *crtc)
> > mtk_crtc->cmdq_client.chan = NULL;
> > }
> > #endif
> > +
> > + for (i = 0; i < mtk_crtc->ddp_comp_nr; i++) {
> > + struct mtk_ddp_comp *comp;
> > +
> > + comp = mtk_crtc->ddp_comp[i];
> > + mtk_ddp_comp_unregister_vblank_cb(comp);
> > + }
> > +
> > drm_crtc_cleanup(crtc);
> > }
> >
> > @@ -616,7 +625,7 @@ static int mtk_drm_crtc_enable_vblank(struct
> > drm_crtc *crtc)
> > struct mtk_drm_crtc *mtk_crtc = to_mtk_crtc(crtc);
> > struct mtk_ddp_comp *comp = mtk_crtc->ddp_comp[0];
> >
> > - mtk_ddp_comp_enable_vblank(comp, mtk_crtc_ddp_irq, &mtk_crtc-
> > > base);
> >
> > + mtk_ddp_comp_enable_vblank(comp);
> >
> > return 0;
> > }
> > @@ -916,6 +925,9 @@ int mtk_drm_crtc_create(struct drm_device
> > *drm_dev,
> > if (comp->funcs->ctm_set)
> > has_ctm = true;
> > }
> > +
> > + mtk_ddp_comp_register_vblank_cb(comp, mtk_crtc_ddp_irq,
> > + &mtk_crtc->base);
> > }
> >
> > for (i = 0; i < mtk_crtc->ddp_comp_nr; i++)
> > diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> > b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> > index b4b682bc1991..028cf76b9531 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> > @@ -297,6 +297,8 @@ static const struct mtk_ddp_comp_funcs ddp_ovl
> > =
> > {
> > .config = mtk_ovl_config,
> > .start = mtk_ovl_start,
> > .stop = mtk_ovl_stop,
> > + .register_vblank_cb = mtk_ovl_register_vblank_cb,
> > + .unregister_vblank_cb = mtk_ovl_unregister_vblank_cb,
> > .enable_vblank = mtk_ovl_enable_vblank,
> > .disable_vblank = mtk_ovl_disable_vblank,
> > .supported_rotations = mtk_ovl_supported_rotations,
> > @@ -321,6 +323,8 @@ static const struct mtk_ddp_comp_funcs ddp_rdma
> > =
> > {
> > .config = mtk_rdma_config,
> > .start = mtk_rdma_start,
> > .stop = mtk_rdma_stop,
> > + .register_vblank_cb = mtk_rdma_register_vblank_cb,
> > + .unregister_vblank_cb = mtk_rdma_unregister_vblank_cb,
> > .enable_vblank = mtk_rdma_enable_vblank,
> > .disable_vblank = mtk_rdma_disable_vblank,
> > .layer_nr = mtk_rdma_layer_nr,
> > diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h
> > b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h
> > index 4c6a98662305..b83f24cb045f 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h
> > +++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h
> > @@ -48,9 +48,11 @@ struct mtk_ddp_comp_funcs {
> > unsigned int bpc, struct cmdq_pkt *cmdq_pkt);
> > void (*start)(struct device *dev);
> > void (*stop)(struct device *dev);
> > - void (*enable_vblank)(struct device *dev,
> > - void (*vblank_cb)(void *),
> > - void *vblank_cb_data);
> > + void (*register_vblank_cb)(struct device *dev,
> > + void (*vblank_cb)(void *),
> > + void *vblank_cb_data);
> > + void (*unregister_vblank_cb)(struct device *dev);
> > + void (*enable_vblank)(struct device *dev);
> > void (*disable_vblank)(struct device *dev);
> > unsigned int (*supported_rotations)(struct device *dev);
> > unsigned int (*layer_nr)(struct device *dev);
> > @@ -111,12 +113,25 @@ static inline void mtk_ddp_comp_stop(struct
> > mtk_ddp_comp *comp)
> > comp->funcs->stop(comp->dev);
> > }
> >
> > -static inline void mtk_ddp_comp_enable_vblank(struct mtk_ddp_comp
> > *comp,
> > - void (*vblank_cb)(void
> > *),
> > - void *vblank_cb_data)
> > +static inline void mtk_ddp_comp_register_vblank_cb(struct
> > mtk_ddp_comp *comp,
> > + void
> > (*vblank_cb)(void *),
> > + void
> > *vblank_cb_data)
> > +{
> > + if (comp->funcs && comp->funcs->register_vblank_cb)
> > + comp->funcs->register_vblank_cb(comp->dev, vblank_cb,
> > + vblank_cb_data);
> > +}
> > +
> > +static inline void mtk_ddp_comp_unregister_vblank_cb(struct
> > mtk_ddp_comp *comp)
> > +{
> > + if (comp->funcs && comp->funcs->unregister_vblank_cb)
> > + comp->funcs->unregister_vblank_cb(comp->dev);
> > +}
> > +
> > +static inline void mtk_ddp_comp_enable_vblank(struct mtk_ddp_comp
> > *comp)
> > {
> > if (comp->funcs && comp->funcs->enable_vblank)
> > - comp->funcs->enable_vblank(comp->dev, vblank_cb,
> > vblank_cb_data);
> > + comp->funcs->enable_vblank(comp->dev);
> > }
> >
> > static inline void mtk_ddp_comp_disable_vblank(struct mtk_ddp_comp
> > *comp)
>
>
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