diff mbox series

[v3,01/12] drm/bridge: Fix the stop condition of drm_bridge_chain_pre_enable()

Message ID 20210402152701.v3.1.If62a003f76a2bc4ccc6c53565becc05d2aad4430@changeid
State Superseded
Headers show
Series drm: Fix EDID reading on ti-sn65dsi86 | expand

Commit Message

Doug Anderson April 2, 2021, 10:28 p.m. UTC
The drm_bridge_chain_pre_enable() is not the proper opposite of
drm_bridge_chain_post_disable(). It continues along the chain to
_before_ the starting bridge. Let's fix that.

Fixes: 05193dc38197 ("drm/bridge: Make the bridge chain a double-linked list")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
---

(no changes since v1)

 drivers/gpu/drm/drm_bridge.c | 3 +++
 1 file changed, 3 insertions(+)

Comments

Doug Anderson April 15, 2021, 1:19 a.m. UTC | #1
Hi,

On Sun, Apr 4, 2021 at 5:50 PM Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
>
> Hi Doug,
>
> Thank you for the patch.
>
> On Fri, Apr 02, 2021 at 03:28:35PM -0700, Douglas Anderson wrote:
> > The drm_bridge_chain_pre_enable() is not the proper opposite of
> > drm_bridge_chain_post_disable(). It continues along the chain to
> > _before_ the starting bridge. Let's fix that.
> >
> > Fixes: 05193dc38197 ("drm/bridge: Make the bridge chain a double-linked list")
> > Signed-off-by: Douglas Anderson <dianders@chromium.org>
> > Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
> > ---
> >
> > (no changes since v1)
> >
> >  drivers/gpu/drm/drm_bridge.c | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
> > index 64f0effb52ac..044acd07c153 100644
> > --- a/drivers/gpu/drm/drm_bridge.c
> > +++ b/drivers/gpu/drm/drm_bridge.c
> > @@ -522,6 +522,9 @@ void drm_bridge_chain_pre_enable(struct drm_bridge *bridge)
> >       list_for_each_entry_reverse(iter, &encoder->bridge_chain, chain_node) {
> >               if (iter->funcs->pre_enable)
> >                       iter->funcs->pre_enable(iter);
> > +
> > +             if (iter == bridge)
> > +                     break;
>
> This looks good as it matches drm_atomic_bridge_chain_disable().
>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

Thanks for your review here and several of the other patches. Can you
suggest any plan for getting them landed? It would at least be nice to
get the non-controversial ones landed.


> I'm curious though, given that the bridge passed to the function should
> be the one closest to the encoder, does this make a difference ?

Yes, that's how I discovered it originally. Let's see. So if I don't
have this patch but have the rest of the series then I get a splat at
bootup. This shows that dsi_mgr_bridge_pre_enable() must be "earlier"
in the chain than my bridge chip. Here's the splat:

 msm_dsi_host_get_phy_clk_req: unable to calc clk rate, -22
 ------------[ cut here ]------------
 disp_cc_mdss_ahb_clk status stuck at 'off'
 WARNING: CPU: 7 PID: 404 at drivers/clk/qcom/clk-branch.c:92
clk_branch_toggle+0x194/0x280
 Modules linked in: joydev
 CPU: 7 PID: 404 Comm: frecon Tainted: G    B             5.12.0-rc3-lockdep+ #2
 Hardware name: Google Lazor (rev1 - 2) with LTE (DT)
 pstate: 60400089 (nZCv daIf +PAN -UAO -TCO BTYPE=--)
 pc : clk_branch_toggle+0x194/0x280
 lr : clk_branch_toggle+0x190/0x280
 ...
 Call trace:
  clk_branch_toggle+0x194/0x280
  clk_branch2_enable+0x28/0x34
  clk_core_enable+0x2f4/0x6b4
  clk_enable+0x54/0x74
  dsi_phy_enable_resource+0x80/0xd8
  msm_dsi_phy_enable+0xa8/0x4a8
  enable_phy+0x9c/0xf4
  dsi_mgr_bridge_pre_enable+0x23c/0x4b0
  drm_bridge_chain_pre_enable+0xac/0xe4
  ti_sn_bridge_connector_get_modes+0x134/0x1b8
  drm_helper_probe_single_connector_modes+0x49c/0x1358
  drm_mode_getconnector+0x460/0xe98
  drm_ioctl_kernel+0x144/0x228
  drm_ioctl+0x418/0x7cc
  drm_compat_ioctl+0x1bc/0x230
  __arm64_compat_sys_ioctl+0x14c/0x188
  el0_svc_common+0x128/0x23c
  do_el0_svc_compat+0x50/0x60
  el0_svc_compat+0x24/0x34
  el0_sync_compat_handler+0xc0/0xf0
  el0_sync_compat+0x174/0x180
Laurent Pinchart April 15, 2021, 1:56 a.m. UTC | #2
Hi Doug,

On Wed, Apr 14, 2021 at 06:19:13PM -0700, Doug Anderson wrote:
> On Sun, Apr 4, 2021 at 5:50 PM Laurent Pinchart wrote:

> > On Fri, Apr 02, 2021 at 03:28:35PM -0700, Douglas Anderson wrote:

> > > The drm_bridge_chain_pre_enable() is not the proper opposite of

> > > drm_bridge_chain_post_disable(). It continues along the chain to

> > > _before_ the starting bridge. Let's fix that.

> > >

> > > Fixes: 05193dc38197 ("drm/bridge: Make the bridge chain a double-linked list")

> > > Signed-off-by: Douglas Anderson <dianders@chromium.org>

> > > Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>

> > > ---

> > >

> > > (no changes since v1)

> > >

> > >  drivers/gpu/drm/drm_bridge.c | 3 +++

> > >  1 file changed, 3 insertions(+)

> > >

> > > diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c

> > > index 64f0effb52ac..044acd07c153 100644

> > > --- a/drivers/gpu/drm/drm_bridge.c

> > > +++ b/drivers/gpu/drm/drm_bridge.c

> > > @@ -522,6 +522,9 @@ void drm_bridge_chain_pre_enable(struct drm_bridge *bridge)

> > >       list_for_each_entry_reverse(iter, &encoder->bridge_chain, chain_node) {

> > >               if (iter->funcs->pre_enable)

> > >                       iter->funcs->pre_enable(iter);

> > > +

> > > +             if (iter == bridge)

> > > +                     break;

> >

> > This looks good as it matches drm_atomic_bridge_chain_disable().

> >

> > Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> 

> Thanks for your review here and several of the other patches. Can you

> suggest any plan for getting them landed? It would at least be nice to

> get the non-controversial ones landed.


Do you have commit access to drm-misc ? If not, given your
contributions, I think you qualify for it.

> > I'm curious though, given that the bridge passed to the function should

> > be the one closest to the encoder, does this make a difference ?

> 

> Yes, that's how I discovered it originally. Let's see. So if I don't

> have this patch but have the rest of the series then I get a splat at

> bootup. This shows that dsi_mgr_bridge_pre_enable() must be "earlier"

> in the chain than my bridge chip. Here's the splat:


Right, I think it's caused by a later patch in the series calling this
function with a different bridge than the one closest to the encoder.

>  msm_dsi_host_get_phy_clk_req: unable to calc clk rate, -22

>  ------------[ cut here ]------------

>  disp_cc_mdss_ahb_clk status stuck at 'off'

>  WARNING: CPU: 7 PID: 404 at drivers/clk/qcom/clk-branch.c:92

> clk_branch_toggle+0x194/0x280

>  Modules linked in: joydev

>  CPU: 7 PID: 404 Comm: frecon Tainted: G    B             5.12.0-rc3-lockdep+ #2

>  Hardware name: Google Lazor (rev1 - 2) with LTE (DT)

>  pstate: 60400089 (nZCv daIf +PAN -UAO -TCO BTYPE=--)

>  pc : clk_branch_toggle+0x194/0x280

>  lr : clk_branch_toggle+0x190/0x280

>  ...

>  Call trace:

>   clk_branch_toggle+0x194/0x280

>   clk_branch2_enable+0x28/0x34

>   clk_core_enable+0x2f4/0x6b4

>   clk_enable+0x54/0x74

>   dsi_phy_enable_resource+0x80/0xd8

>   msm_dsi_phy_enable+0xa8/0x4a8

>   enable_phy+0x9c/0xf4

>   dsi_mgr_bridge_pre_enable+0x23c/0x4b0

>   drm_bridge_chain_pre_enable+0xac/0xe4

>   ti_sn_bridge_connector_get_modes+0x134/0x1b8

>   drm_helper_probe_single_connector_modes+0x49c/0x1358

>   drm_mode_getconnector+0x460/0xe98

>   drm_ioctl_kernel+0x144/0x228

>   drm_ioctl+0x418/0x7cc

>   drm_compat_ioctl+0x1bc/0x230

>   __arm64_compat_sys_ioctl+0x14c/0x188

>   el0_svc_common+0x128/0x23c

>   do_el0_svc_compat+0x50/0x60

>   el0_svc_compat+0x24/0x34

>   el0_sync_compat_handler+0xc0/0xf0

>   el0_sync_compat+0x174/0x180


-- 
Regards,

Laurent Pinchart
diff mbox series

Patch

diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
index 64f0effb52ac..044acd07c153 100644
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -522,6 +522,9 @@  void drm_bridge_chain_pre_enable(struct drm_bridge *bridge)
 	list_for_each_entry_reverse(iter, &encoder->bridge_chain, chain_node) {
 		if (iter->funcs->pre_enable)
 			iter->funcs->pre_enable(iter);
+
+		if (iter == bridge)
+			break;
 	}
 }
 EXPORT_SYMBOL(drm_bridge_chain_pre_enable);