[PATCH] drm: bridge: dw-hdmi: Avoid resetting force in the detect function

[PATCH] drm: bridge: dw-hdmi: Avoid resetting force in the detect function

[Jonathan Liu]

It has been observed that resetting force in the detect function can
result in the PHY being powered down in response to hot-plug detect
being asserted, even when the HDMI connector is forced on.

Enabling debug messages and adding a call to dump_stack() in
dw_hdmi_phy_power_off() shows the following in dmesg:
[  160.637413] dwhdmi-rockchip ff940000.hdmi: EVENT=plugin
[  160.637433] dwhdmi-rockchip ff940000.hdmi: PHY powered down in 0 iterations

Call trace:
dw_hdmi_phy_power_off
dw_hdmi_phy_disable
dw_hdmi_update_power
dw_hdmi_detect
dw_hdmi_connector_detect
drm_helper_probe_detect_ctx
drm_helper_hpd_irq_event
dw_hdmi_irq
irq_thread_fn
irq_thread
kthread
ret_from_fork

Fixes: 381f05a7a842 ("drm: bridge/dw_hdmi: add connector mode forcing")
Signed-off-by: Jonathan Liu <net147@gmail.com>
---
 drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
index 748df1cacd2b..0c79a9ba48bb 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
@@ -2327,12 +2327,6 @@ static enum drm_connector_status dw_hdmi_detect(struct dw_hdmi *hdmi)
 {
 	enum drm_connector_status result;
 
-	mutex_lock(&hdmi->mutex);
-	hdmi->force = DRM_FORCE_UNSPECIFIED;
-	dw_hdmi_update_power(hdmi);
-	dw_hdmi_update_phy_mask(hdmi);
-	mutex_unlock(&hdmi->mutex);
-
 	result = hdmi->phy.ops->read_hpd(hdmi, hdmi->phy.data);
 
 	mutex_lock(&hdmi->mutex);
-- 
2.29.1


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Re: [PATCH] drm: bridge: dw-hdmi: Avoid resetting force in the detect function

[Sam Ravnborg]

Russell,

On Sat, Oct 31, 2020 at 07:17:47PM +1100, Jonathan Liu wrote:
> It has been observed that resetting force in the detect function can
> result in the PHY being powered down in response to hot-plug detect
> being asserted, even when the HDMI connector is forced on.
> 
> Enabling debug messages and adding a call to dump_stack() in
> dw_hdmi_phy_power_off() shows the following in dmesg:
> [  160.637413] dwhdmi-rockchip ff940000.hdmi: EVENT=plugin
> [  160.637433] dwhdmi-rockchip ff940000.hdmi: PHY powered down in 0 iterations
> 
> Call trace:
> dw_hdmi_phy_power_off
> dw_hdmi_phy_disable
> dw_hdmi_update_power
> dw_hdmi_detect
> dw_hdmi_connector_detect
> drm_helper_probe_detect_ctx
> drm_helper_hpd_irq_event
> dw_hdmi_irq
> irq_thread_fn
> irq_thread
> kthread
> ret_from_fork
> 
> Fixes: 381f05a7a842 ("drm: bridge/dw_hdmi: add connector mode forcing")
> Signed-off-by: Jonathan Liu <net147@gmail.com>

you are the original author of this code - any comments on this patch?

	Sam

> ---
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 6 ------
>  1 file changed, 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> index 748df1cacd2b..0c79a9ba48bb 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> @@ -2327,12 +2327,6 @@ static enum drm_connector_status dw_hdmi_detect(struct dw_hdmi *hdmi)
>  {
>  	enum drm_connector_status result;
>  
> -	mutex_lock(&hdmi->mutex);
> -	hdmi->force = DRM_FORCE_UNSPECIFIED;
> -	dw_hdmi_update_power(hdmi);
> -	dw_hdmi_update_phy_mask(hdmi);
> -	mutex_unlock(&hdmi->mutex);
> -
>  	result = hdmi->phy.ops->read_hpd(hdmi, hdmi->phy.data);
>  
>  	mutex_lock(&hdmi->mutex);
> -- 
> 2.29.1
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

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Re: [PATCH] drm: bridge: dw-hdmi: Avoid resetting force in the detect function

[Russell King - ARM Linux admin]

On Sun, Nov 08, 2020 at 10:53:22AM +0100, Sam Ravnborg wrote:
> Russell,
> 
> On Sat, Oct 31, 2020 at 07:17:47PM +1100, Jonathan Liu wrote:
> > It has been observed that resetting force in the detect function can
> > result in the PHY being powered down in response to hot-plug detect
> > being asserted, even when the HDMI connector is forced on.
> > 
> > Enabling debug messages and adding a call to dump_stack() in
> > dw_hdmi_phy_power_off() shows the following in dmesg:
> > [  160.637413] dwhdmi-rockchip ff940000.hdmi: EVENT=plugin
> > [  160.637433] dwhdmi-rockchip ff940000.hdmi: PHY powered down in 0 iterations
> > 
> > Call trace:
> > dw_hdmi_phy_power_off
> > dw_hdmi_phy_disable
> > dw_hdmi_update_power
> > dw_hdmi_detect
> > dw_hdmi_connector_detect
> > drm_helper_probe_detect_ctx
> > drm_helper_hpd_irq_event
> > dw_hdmi_irq
> > irq_thread_fn
> > irq_thread
> > kthread
> > ret_from_fork
> > 
> > Fixes: 381f05a7a842 ("drm: bridge/dw_hdmi: add connector mode forcing")
> > Signed-off-by: Jonathan Liu <net147@gmail.com>
> 
> you are the original author of this code - any comments on this patch?

No further comments beyond what has already been discussed, and the
long and short of it is it's been so long that I don't remember why
that code was there. Given that, I'm not even in a position to ack
the change. Sorry.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!

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Re: [PATCH] drm: bridge: dw-hdmi: Avoid resetting force in the detect function

[Sam Ravnborg]

Hi Russell,

On Sun, Nov 08, 2020 at 09:57:25AM +0000, Russell King - ARM Linux admin wrote:
> On Sun, Nov 08, 2020 at 10:53:22AM +0100, Sam Ravnborg wrote:
> > Russell,
> > 
> > On Sat, Oct 31, 2020 at 07:17:47PM +1100, Jonathan Liu wrote:
> > > It has been observed that resetting force in the detect function can
> > > result in the PHY being powered down in response to hot-plug detect
> > > being asserted, even when the HDMI connector is forced on.
> > > 
> > > Enabling debug messages and adding a call to dump_stack() in
> > > dw_hdmi_phy_power_off() shows the following in dmesg:
> > > [  160.637413] dwhdmi-rockchip ff940000.hdmi: EVENT=plugin
> > > [  160.637433] dwhdmi-rockchip ff940000.hdmi: PHY powered down in 0 iterations
> > > 
> > > Call trace:
> > > dw_hdmi_phy_power_off
> > > dw_hdmi_phy_disable
> > > dw_hdmi_update_power
> > > dw_hdmi_detect
> > > dw_hdmi_connector_detect
> > > drm_helper_probe_detect_ctx
> > > drm_helper_hpd_irq_event
> > > dw_hdmi_irq
> > > irq_thread_fn
> > > irq_thread
> > > kthread
> > > ret_from_fork
> > > 
> > > Fixes: 381f05a7a842 ("drm: bridge/dw_hdmi: add connector mode forcing")
> > > Signed-off-by: Jonathan Liu <net147@gmail.com>
> > 
> > you are the original author of this code - any comments on this patch?
> 
> No further comments beyond what has already been discussed, and the
> long and short of it is it's been so long that I don't remember why
> that code was there. Given that, I'm not even in a position to ack
> the change. Sorry.
Thanks for the quick reply.

Given that this fixes a problem for Jonathan I will apply this to -fixes
if there is no other feedback the next couple of days.
If it introduces regression we can take it from there.

Jonathan - please ping me if I forget.

	Sam

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Re: [PATCH] drm: bridge: dw-hdmi: Avoid resetting force in the detect function

[Jonathan Liu]

Hi Sam,

On Sun, 8 Nov 2020 at 21:47, Sam Ravnborg <sam@ravnborg.org> wrote:
>
> Hi Russell,
>
> On Sun, Nov 08, 2020 at 09:57:25AM +0000, Russell King - ARM Linux admin wrote:
> > On Sun, Nov 08, 2020 at 10:53:22AM +0100, Sam Ravnborg wrote:
> > > Russell,
> > >
> > > On Sat, Oct 31, 2020 at 07:17:47PM +1100, Jonathan Liu wrote:
> > > > It has been observed that resetting force in the detect function can
> > > > result in the PHY being powered down in response to hot-plug detect
> > > > being asserted, even when the HDMI connector is forced on.
> > > >
> > > > Enabling debug messages and adding a call to dump_stack() in
> > > > dw_hdmi_phy_power_off() shows the following in dmesg:
> > > > [  160.637413] dwhdmi-rockchip ff940000.hdmi: EVENT=plugin
> > > > [  160.637433] dwhdmi-rockchip ff940000.hdmi: PHY powered down in 0 iterations
> > > >
> > > > Call trace:
> > > > dw_hdmi_phy_power_off
> > > > dw_hdmi_phy_disable
> > > > dw_hdmi_update_power
> > > > dw_hdmi_detect
> > > > dw_hdmi_connector_detect
> > > > drm_helper_probe_detect_ctx
> > > > drm_helper_hpd_irq_event
> > > > dw_hdmi_irq
> > > > irq_thread_fn
> > > > irq_thread
> > > > kthread
> > > > ret_from_fork
> > > >
> > > > Fixes: 381f05a7a842 ("drm: bridge/dw_hdmi: add connector mode forcing")
> > > > Signed-off-by: Jonathan Liu <net147@gmail.com>
> > >
> > > you are the original author of this code - any comments on this patch?
> >
> > No further comments beyond what has already been discussed, and the
> > long and short of it is it's been so long that I don't remember why
> > that code was there. Given that, I'm not even in a position to ack
> > the change. Sorry.
> Thanks for the quick reply.
>
> Given that this fixes a problem for Jonathan I will apply this to -fixes
> if there is no other feedback the next couple of days.
> If it introduces regression we can take it from there.
>
> Jonathan - please ping me if I forget.
>
>         Sam

Ping.

Regards,
Jonathan

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Re: [PATCH] drm: bridge: dw-hdmi: Avoid resetting force in the detect function

[Sam Ravnborg]

Hi Jonathan
On Sat, Oct 31, 2020 at 07:17:47PM +1100, Jonathan Liu wrote:
> It has been observed that resetting force in the detect function can
> result in the PHY being powered down in response to hot-plug detect
> being asserted, even when the HDMI connector is forced on.
> 
> Enabling debug messages and adding a call to dump_stack() in
> dw_hdmi_phy_power_off() shows the following in dmesg:
> [  160.637413] dwhdmi-rockchip ff940000.hdmi: EVENT=plugin
> [  160.637433] dwhdmi-rockchip ff940000.hdmi: PHY powered down in 0 iterations
> 
> Call trace:
> dw_hdmi_phy_power_off
> dw_hdmi_phy_disable
> dw_hdmi_update_power
> dw_hdmi_detect
> dw_hdmi_connector_detect
> drm_helper_probe_detect_ctx
> drm_helper_hpd_irq_event
> dw_hdmi_irq
> irq_thread_fn
> irq_thread
> kthread
> ret_from_fork
> 
> Fixes: 381f05a7a842 ("drm: bridge/dw_hdmi: add connector mode forcing")
> Signed-off-by: Jonathan Liu <net147@gmail.com>

Applied to drm-misc-fixes.

	Sam

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