* [PATCH] lontium-lt9611: check a different register bit for HDMI sensing
@ 2021-11-17 2:07 ` Peter Collingbourne
0 siblings, 0 replies; 13+ messages in thread
From: Peter Collingbourne @ 2021-11-17 2:07 UTC (permalink / raw)
To: Robert Foss, Vinod Koul, John Stultz, Anibal Limon, Bjorn Andersson
Cc: Peter Collingbourne, dri-devel, linux-kernel
It has been observed that with certain monitors such as the HP Z27n,
the register 0x825e reads a value of 0x79 when the HDMI cable is
connected and 0x78 when it is disconnected, i.e. bit 0 appears
to correspond to the HDMI connection status and bit 2 is never
set. Therefore, change the driver to check bit 0 instead of bit 2.
Signed-off-by: Peter Collingbourne <pcc@google.com>
Link: https://linux-review.googlesource.com/id/I7e76411127e1ce4988a3f6d0c8ba5f1c3d880c23
---
N.B. I don't currently have easy access to a monitor that works
with the existing driver, so it would be great if people with
monitors that currently work could test this patch to make sure
that it doesn't introduce any regressions. Otherwise I will change
it to check both bits.
drivers/gpu/drm/bridge/lontium-lt9611.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/bridge/lontium-lt9611.c b/drivers/gpu/drm/bridge/lontium-lt9611.c
index 29b1ce2140ab..71f1db802916 100644
--- a/drivers/gpu/drm/bridge/lontium-lt9611.c
+++ b/drivers/gpu/drm/bridge/lontium-lt9611.c
@@ -586,7 +586,7 @@ lt9611_connector_detect(struct drm_connector *connector, bool force)
int connected = 0;
regmap_read(lt9611->regmap, 0x825e, ®_val);
- connected = (reg_val & BIT(2));
+ connected = (reg_val & BIT(0));
lt9611->status = connected ? connector_status_connected :
connector_status_disconnected;
@@ -926,7 +926,7 @@ static enum drm_connector_status lt9611_bridge_detect(struct drm_bridge *bridge)
int connected;
regmap_read(lt9611->regmap, 0x825e, ®_val);
- connected = reg_val & BIT(2);
+ connected = reg_val & BIT(0);
lt9611->status = connected ? connector_status_connected :
connector_status_disconnected;
--
2.34.0.rc1.387.gb447b232ab-goog
^ permalink raw reply related [flat|nested] 13+ messages in thread
* [PATCH] lontium-lt9611: check a different register bit for HDMI sensing
@ 2021-11-17 2:07 ` Peter Collingbourne
0 siblings, 0 replies; 13+ messages in thread
From: Peter Collingbourne @ 2021-11-17 2:07 UTC (permalink / raw)
To: Robert Foss, Vinod Koul, John Stultz, Anibal Limon, Bjorn Andersson
Cc: Peter Collingbourne, linux-kernel, dri-devel
It has been observed that with certain monitors such as the HP Z27n,
the register 0x825e reads a value of 0x79 when the HDMI cable is
connected and 0x78 when it is disconnected, i.e. bit 0 appears
to correspond to the HDMI connection status and bit 2 is never
set. Therefore, change the driver to check bit 0 instead of bit 2.
Signed-off-by: Peter Collingbourne <pcc@google.com>
Link: https://linux-review.googlesource.com/id/I7e76411127e1ce4988a3f6d0c8ba5f1c3d880c23
---
N.B. I don't currently have easy access to a monitor that works
with the existing driver, so it would be great if people with
monitors that currently work could test this patch to make sure
that it doesn't introduce any regressions. Otherwise I will change
it to check both bits.
drivers/gpu/drm/bridge/lontium-lt9611.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/bridge/lontium-lt9611.c b/drivers/gpu/drm/bridge/lontium-lt9611.c
index 29b1ce2140ab..71f1db802916 100644
--- a/drivers/gpu/drm/bridge/lontium-lt9611.c
+++ b/drivers/gpu/drm/bridge/lontium-lt9611.c
@@ -586,7 +586,7 @@ lt9611_connector_detect(struct drm_connector *connector, bool force)
int connected = 0;
regmap_read(lt9611->regmap, 0x825e, ®_val);
- connected = (reg_val & BIT(2));
+ connected = (reg_val & BIT(0));
lt9611->status = connected ? connector_status_connected :
connector_status_disconnected;
@@ -926,7 +926,7 @@ static enum drm_connector_status lt9611_bridge_detect(struct drm_bridge *bridge)
int connected;
regmap_read(lt9611->regmap, 0x825e, ®_val);
- connected = reg_val & BIT(2);
+ connected = reg_val & BIT(0);
lt9611->status = connected ? connector_status_connected :
connector_status_disconnected;
--
2.34.0.rc1.387.gb447b232ab-goog
^ permalink raw reply related [flat|nested] 13+ messages in thread
* Re: [PATCH] lontium-lt9611: check a different register bit for HDMI sensing
2021-11-17 2:07 ` Peter Collingbourne
@ 2021-11-17 4:47 ` John Stultz
-1 siblings, 0 replies; 13+ messages in thread
From: John Stultz @ 2021-11-17 4:47 UTC (permalink / raw)
To: Peter Collingbourne
Cc: Robert Foss, Vinod Koul, Anibal Limon, Bjorn Andersson,
dri-devel, linux-kernel
On Tue, Nov 16, 2021 at 6:07 PM Peter Collingbourne <pcc@google.com> wrote:
>
> It has been observed that with certain monitors such as the HP Z27n,
> the register 0x825e reads a value of 0x79 when the HDMI cable is
> connected and 0x78 when it is disconnected, i.e. bit 0 appears
> to correspond to the HDMI connection status and bit 2 is never
> set. Therefore, change the driver to check bit 0 instead of bit 2.
>
> Signed-off-by: Peter Collingbourne <pcc@google.com>
> Link: https://linux-review.googlesource.com/id/I7e76411127e1ce4988a3f6d0c8ba5f1c3d880c23
> ---
> N.B. I don't currently have easy access to a monitor that works
> with the existing driver, so it would be great if people with
> monitors that currently work could test this patch to make sure
> that it doesn't introduce any regressions. Otherwise I will change
> it to check both bits.
So very interesting! I gave this a spin with my monitors and it works fine.
Vinod: Can you check the datasheet to see if the wrong bit is being used here?
thanks
-john
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH] lontium-lt9611: check a different register bit for HDMI sensing
@ 2021-11-17 4:47 ` John Stultz
0 siblings, 0 replies; 13+ messages in thread
From: John Stultz @ 2021-11-17 4:47 UTC (permalink / raw)
To: Peter Collingbourne
Cc: Anibal Limon, linux-kernel, dri-devel, Bjorn Andersson,
Vinod Koul, Robert Foss
On Tue, Nov 16, 2021 at 6:07 PM Peter Collingbourne <pcc@google.com> wrote:
>
> It has been observed that with certain monitors such as the HP Z27n,
> the register 0x825e reads a value of 0x79 when the HDMI cable is
> connected and 0x78 when it is disconnected, i.e. bit 0 appears
> to correspond to the HDMI connection status and bit 2 is never
> set. Therefore, change the driver to check bit 0 instead of bit 2.
>
> Signed-off-by: Peter Collingbourne <pcc@google.com>
> Link: https://linux-review.googlesource.com/id/I7e76411127e1ce4988a3f6d0c8ba5f1c3d880c23
> ---
> N.B. I don't currently have easy access to a monitor that works
> with the existing driver, so it would be great if people with
> monitors that currently work could test this patch to make sure
> that it doesn't introduce any regressions. Otherwise I will change
> it to check both bits.
So very interesting! I gave this a spin with my monitors and it works fine.
Vinod: Can you check the datasheet to see if the wrong bit is being used here?
thanks
-john
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH] lontium-lt9611: check a different register bit for HDMI sensing
2021-11-17 2:07 ` Peter Collingbourne
(?)
(?)
@ 2021-11-17 4:49 ` Anibal Limon
2021-11-17 5:09 ` Vinod Koul
-1 siblings, 1 reply; 13+ messages in thread
From: Anibal Limon @ 2021-11-17 4:49 UTC (permalink / raw)
To: Peter Collingbourne
Cc: linux-kernel, dri-devel, Bjorn Andersson, Vinod Koul,
Robert Foss, Dmitry Baryshkov
[-- Attachment #1: Type: text/plain, Size: 2216 bytes --]
Dmitry,
May be this is the reason of my HP monitor not working in RB5.
Regards,
Anibal
El mar., 16 de noviembre de 2021 20:07, Peter Collingbourne <pcc@google.com>
escribió:
> It has been observed that with certain monitors such as the HP Z27n,
> the register 0x825e reads a value of 0x79 when the HDMI cable is
> connected and 0x78 when it is disconnected, i.e. bit 0 appears
> to correspond to the HDMI connection status and bit 2 is never
> set. Therefore, change the driver to check bit 0 instead of bit 2.
>
> Signed-off-by: Peter Collingbourne <pcc@google.com>
> Link:
> https://linux-review.googlesource.com/id/I7e76411127e1ce4988a3f6d0c8ba5f1c3d880c23
> ---
> N.B. I don't currently have easy access to a monitor that works
> with the existing driver, so it would be great if people with
> monitors that currently work could test this patch to make sure
> that it doesn't introduce any regressions. Otherwise I will change
> it to check both bits.
>
> drivers/gpu/drm/bridge/lontium-lt9611.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/lontium-lt9611.c
> b/drivers/gpu/drm/bridge/lontium-lt9611.c
> index 29b1ce2140ab..71f1db802916 100644
> --- a/drivers/gpu/drm/bridge/lontium-lt9611.c
> +++ b/drivers/gpu/drm/bridge/lontium-lt9611.c
> @@ -586,7 +586,7 @@ lt9611_connector_detect(struct drm_connector
> *connector, bool force)
> int connected = 0;
>
> regmap_read(lt9611->regmap, 0x825e, ®_val);
> - connected = (reg_val & BIT(2));
> + connected = (reg_val & BIT(0));
>
> lt9611->status = connected ? connector_status_connected :
> connector_status_disconnected;
> @@ -926,7 +926,7 @@ static enum drm_connector_status
> lt9611_bridge_detect(struct drm_bridge *bridge)
> int connected;
>
> regmap_read(lt9611->regmap, 0x825e, ®_val);
> - connected = reg_val & BIT(2);
> + connected = reg_val & BIT(0);
>
> lt9611->status = connected ? connector_status_connected :
> connector_status_disconnected;
> --
> 2.34.0.rc1.387.gb447b232ab-goog
>
>
[-- Attachment #2: Type: text/html, Size: 2995 bytes --]
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH] lontium-lt9611: check a different register bit for HDMI sensing
2021-11-17 4:49 ` Anibal Limon
@ 2021-11-17 5:09 ` Vinod Koul
0 siblings, 0 replies; 13+ messages in thread
From: Vinod Koul @ 2021-11-17 5:09 UTC (permalink / raw)
To: Anibal Limon
Cc: Peter Collingbourne, Robert Foss, John Stultz, Bjorn Andersson,
dri-devel, linux-kernel, Dmitry Baryshkov
On 16-11-21, 22:49, Anibal Limon wrote:
> Dmitry,
>
> May be this is the reason of my HP monitor not working in RB5.
Rb5 has Lt9611UXC
>
> Regards,
> Anibal
>
> El mar., 16 de noviembre de 2021 20:07, Peter Collingbourne <pcc@google.com>
> escribió:
>
> > It has been observed that with certain monitors such as the HP Z27n,
> > the register 0x825e reads a value of 0x79 when the HDMI cable is
> > connected and 0x78 when it is disconnected, i.e. bit 0 appears
> > to correspond to the HDMI connection status and bit 2 is never
> > set. Therefore, change the driver to check bit 0 instead of bit 2.
> >
> > Signed-off-by: Peter Collingbourne <pcc@google.com>
> > Link:
> > https://linux-review.googlesource.com/id/I7e76411127e1ce4988a3f6d0c8ba5f1c3d880c23
> > ---
> > N.B. I don't currently have easy access to a monitor that works
> > with the existing driver, so it would be great if people with
> > monitors that currently work could test this patch to make sure
> > that it doesn't introduce any regressions. Otherwise I will change
> > it to check both bits.
> >
> > drivers/gpu/drm/bridge/lontium-lt9611.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/bridge/lontium-lt9611.c
> > b/drivers/gpu/drm/bridge/lontium-lt9611.c
> > index 29b1ce2140ab..71f1db802916 100644
> > --- a/drivers/gpu/drm/bridge/lontium-lt9611.c
> > +++ b/drivers/gpu/drm/bridge/lontium-lt9611.c
> > @@ -586,7 +586,7 @@ lt9611_connector_detect(struct drm_connector
> > *connector, bool force)
> > int connected = 0;
> >
> > regmap_read(lt9611->regmap, 0x825e, ®_val);
> > - connected = (reg_val & BIT(2));
> > + connected = (reg_val & BIT(0));
> >
> > lt9611->status = connected ? connector_status_connected :
> > connector_status_disconnected;
> > @@ -926,7 +926,7 @@ static enum drm_connector_status
> > lt9611_bridge_detect(struct drm_bridge *bridge)
> > int connected;
> >
> > regmap_read(lt9611->regmap, 0x825e, ®_val);
> > - connected = reg_val & BIT(2);
> > + connected = reg_val & BIT(0);
> >
> > lt9611->status = connected ? connector_status_connected :
> > connector_status_disconnected;
> > --
> > 2.34.0.rc1.387.gb447b232ab-goog
> >
> >
--
~Vinod
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH] lontium-lt9611: check a different register bit for HDMI sensing
@ 2021-11-17 5:09 ` Vinod Koul
0 siblings, 0 replies; 13+ messages in thread
From: Vinod Koul @ 2021-11-17 5:09 UTC (permalink / raw)
To: Anibal Limon
Cc: linux-kernel, dri-devel, Bjorn Andersson, Robert Foss,
Dmitry Baryshkov, Peter Collingbourne
On 16-11-21, 22:49, Anibal Limon wrote:
> Dmitry,
>
> May be this is the reason of my HP monitor not working in RB5.
Rb5 has Lt9611UXC
>
> Regards,
> Anibal
>
> El mar., 16 de noviembre de 2021 20:07, Peter Collingbourne <pcc@google.com>
> escribió:
>
> > It has been observed that with certain monitors such as the HP Z27n,
> > the register 0x825e reads a value of 0x79 when the HDMI cable is
> > connected and 0x78 when it is disconnected, i.e. bit 0 appears
> > to correspond to the HDMI connection status and bit 2 is never
> > set. Therefore, change the driver to check bit 0 instead of bit 2.
> >
> > Signed-off-by: Peter Collingbourne <pcc@google.com>
> > Link:
> > https://linux-review.googlesource.com/id/I7e76411127e1ce4988a3f6d0c8ba5f1c3d880c23
> > ---
> > N.B. I don't currently have easy access to a monitor that works
> > with the existing driver, so it would be great if people with
> > monitors that currently work could test this patch to make sure
> > that it doesn't introduce any regressions. Otherwise I will change
> > it to check both bits.
> >
> > drivers/gpu/drm/bridge/lontium-lt9611.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/bridge/lontium-lt9611.c
> > b/drivers/gpu/drm/bridge/lontium-lt9611.c
> > index 29b1ce2140ab..71f1db802916 100644
> > --- a/drivers/gpu/drm/bridge/lontium-lt9611.c
> > +++ b/drivers/gpu/drm/bridge/lontium-lt9611.c
> > @@ -586,7 +586,7 @@ lt9611_connector_detect(struct drm_connector
> > *connector, bool force)
> > int connected = 0;
> >
> > regmap_read(lt9611->regmap, 0x825e, ®_val);
> > - connected = (reg_val & BIT(2));
> > + connected = (reg_val & BIT(0));
> >
> > lt9611->status = connected ? connector_status_connected :
> > connector_status_disconnected;
> > @@ -926,7 +926,7 @@ static enum drm_connector_status
> > lt9611_bridge_detect(struct drm_bridge *bridge)
> > int connected;
> >
> > regmap_read(lt9611->regmap, 0x825e, ®_val);
> > - connected = reg_val & BIT(2);
> > + connected = reg_val & BIT(0);
> >
> > lt9611->status = connected ? connector_status_connected :
> > connector_status_disconnected;
> > --
> > 2.34.0.rc1.387.gb447b232ab-goog
> >
> >
--
~Vinod
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH] lontium-lt9611: check a different register bit for HDMI sensing
2021-11-17 4:47 ` John Stultz
@ 2021-11-17 5:10 ` Vinod Koul
-1 siblings, 0 replies; 13+ messages in thread
From: Vinod Koul @ 2021-11-17 5:10 UTC (permalink / raw)
To: John Stultz
Cc: Peter Collingbourne, Robert Foss, Anibal Limon, Bjorn Andersson,
dri-devel, linux-kernel
Hi John,
On 16-11-21, 20:47, John Stultz wrote:
> On Tue, Nov 16, 2021 at 6:07 PM Peter Collingbourne <pcc@google.com> wrote:
> >
> > It has been observed that with certain monitors such as the HP Z27n,
> > the register 0x825e reads a value of 0x79 when the HDMI cable is
> > connected and 0x78 when it is disconnected, i.e. bit 0 appears
> > to correspond to the HDMI connection status and bit 2 is never
> > set. Therefore, change the driver to check bit 0 instead of bit 2.
> >
> > Signed-off-by: Peter Collingbourne <pcc@google.com>
> > Link: https://linux-review.googlesource.com/id/I7e76411127e1ce4988a3f6d0c8ba5f1c3d880c23
> > ---
> > N.B. I don't currently have easy access to a monitor that works
> > with the existing driver, so it would be great if people with
> > monitors that currently work could test this patch to make sure
> > that it doesn't introduce any regressions. Otherwise I will change
> > it to check both bits.
>
> So very interesting! I gave this a spin with my monitors and it works fine.
>
> Vinod: Can you check the datasheet to see if the wrong bit is being used here?
Well the document I have does not list this register :(
I have asked Lontium folks about this register description, will update
if I hear back. Meanwhile we can get this patch tested with different
monitors.
Thanks
--
~Vinod
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH] lontium-lt9611: check a different register bit for HDMI sensing
@ 2021-11-17 5:10 ` Vinod Koul
0 siblings, 0 replies; 13+ messages in thread
From: Vinod Koul @ 2021-11-17 5:10 UTC (permalink / raw)
To: John Stultz
Cc: Anibal Limon, linux-kernel, dri-devel, Bjorn Andersson,
Robert Foss, Peter Collingbourne
Hi John,
On 16-11-21, 20:47, John Stultz wrote:
> On Tue, Nov 16, 2021 at 6:07 PM Peter Collingbourne <pcc@google.com> wrote:
> >
> > It has been observed that with certain monitors such as the HP Z27n,
> > the register 0x825e reads a value of 0x79 when the HDMI cable is
> > connected and 0x78 when it is disconnected, i.e. bit 0 appears
> > to correspond to the HDMI connection status and bit 2 is never
> > set. Therefore, change the driver to check bit 0 instead of bit 2.
> >
> > Signed-off-by: Peter Collingbourne <pcc@google.com>
> > Link: https://linux-review.googlesource.com/id/I7e76411127e1ce4988a3f6d0c8ba5f1c3d880c23
> > ---
> > N.B. I don't currently have easy access to a monitor that works
> > with the existing driver, so it would be great if people with
> > monitors that currently work could test this patch to make sure
> > that it doesn't introduce any regressions. Otherwise I will change
> > it to check both bits.
>
> So very interesting! I gave this a spin with my monitors and it works fine.
>
> Vinod: Can you check the datasheet to see if the wrong bit is being used here?
Well the document I have does not list this register :(
I have asked Lontium folks about this register description, will update
if I hear back. Meanwhile we can get this patch tested with different
monitors.
Thanks
--
~Vinod
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH] lontium-lt9611: check a different register bit for HDMI sensing
2021-11-17 2:07 ` Peter Collingbourne
@ 2021-11-30 5:30 ` Vinod Koul
-1 siblings, 0 replies; 13+ messages in thread
From: Vinod Koul @ 2021-11-30 5:30 UTC (permalink / raw)
To: Peter Collingbourne
Cc: Robert Foss, John Stultz, Anibal Limon, Bjorn Andersson,
dri-devel, linux-kernel
On 16-11-21, 18:07, Peter Collingbourne wrote:
> It has been observed that with certain monitors such as the HP Z27n,
> the register 0x825e reads a value of 0x79 when the HDMI cable is
> connected and 0x78 when it is disconnected, i.e. bit 0 appears
> to correspond to the HDMI connection status and bit 2 is never
> set. Therefore, change the driver to check bit 0 instead of bit 2.
So we have got limited information on this but BIT-2 seems to be related
to HPD and empirical data from various monitors supports this, so this
seems the right thing to do.
Reviewed-by: Vinod Koul <vkoul@kernel.org>
--
~Vinod
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH] lontium-lt9611: check a different register bit for HDMI sensing
@ 2021-11-30 5:30 ` Vinod Koul
0 siblings, 0 replies; 13+ messages in thread
From: Vinod Koul @ 2021-11-30 5:30 UTC (permalink / raw)
To: Peter Collingbourne
Cc: Anibal Limon, linux-kernel, dri-devel, Bjorn Andersson, Robert Foss
On 16-11-21, 18:07, Peter Collingbourne wrote:
> It has been observed that with certain monitors such as the HP Z27n,
> the register 0x825e reads a value of 0x79 when the HDMI cable is
> connected and 0x78 when it is disconnected, i.e. bit 0 appears
> to correspond to the HDMI connection status and bit 2 is never
> set. Therefore, change the driver to check bit 0 instead of bit 2.
So we have got limited information on this but BIT-2 seems to be related
to HPD and empirical data from various monitors supports this, so this
seems the right thing to do.
Reviewed-by: Vinod Koul <vkoul@kernel.org>
--
~Vinod
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH] lontium-lt9611: check a different register bit for HDMI sensing
2021-11-30 5:30 ` Vinod Koul
@ 2021-11-30 12:17 ` Robert Foss
-1 siblings, 0 replies; 13+ messages in thread
From: Robert Foss @ 2021-11-30 12:17 UTC (permalink / raw)
To: Vinod Koul
Cc: Peter Collingbourne, John Stultz, Anibal Limon, Bjorn Andersson,
dri-devel, linux-kernel
On Tue, 30 Nov 2021 at 06:30, Vinod Koul <vkoul@kernel.org> wrote:
>
> On 16-11-21, 18:07, Peter Collingbourne wrote:
> > It has been observed that with certain monitors such as the HP Z27n,
> > the register 0x825e reads a value of 0x79 when the HDMI cable is
> > connected and 0x78 when it is disconnected, i.e. bit 0 appears
> > to correspond to the HDMI connection status and bit 2 is never
> > set. Therefore, change the driver to check bit 0 instead of bit 2.
>
> So we have got limited information on this but BIT-2 seems to be related
> to HPD and empirical data from various monitors supports this, so this
> seems the right thing to do.
>
> Reviewed-by: Vinod Koul <vkoul@kernel.org>
>
Applied to drm-misc-next
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH] lontium-lt9611: check a different register bit for HDMI sensing
@ 2021-11-30 12:17 ` Robert Foss
0 siblings, 0 replies; 13+ messages in thread
From: Robert Foss @ 2021-11-30 12:17 UTC (permalink / raw)
To: Vinod Koul
Cc: Anibal Limon, linux-kernel, dri-devel, Bjorn Andersson,
Peter Collingbourne
On Tue, 30 Nov 2021 at 06:30, Vinod Koul <vkoul@kernel.org> wrote:
>
> On 16-11-21, 18:07, Peter Collingbourne wrote:
> > It has been observed that with certain monitors such as the HP Z27n,
> > the register 0x825e reads a value of 0x79 when the HDMI cable is
> > connected and 0x78 when it is disconnected, i.e. bit 0 appears
> > to correspond to the HDMI connection status and bit 2 is never
> > set. Therefore, change the driver to check bit 0 instead of bit 2.
>
> So we have got limited information on this but BIT-2 seems to be related
> to HPD and empirical data from various monitors supports this, so this
> seems the right thing to do.
>
> Reviewed-by: Vinod Koul <vkoul@kernel.org>
>
Applied to drm-misc-next
^ permalink raw reply [flat|nested] 13+ messages in thread
end of thread, other threads:[~2021-11-30 12:17 UTC | newest]
Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed)
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2021-11-17 2:07 [PATCH] lontium-lt9611: check a different register bit for HDMI sensing Peter Collingbourne
2021-11-17 2:07 ` Peter Collingbourne
2021-11-17 4:47 ` John Stultz
2021-11-17 4:47 ` John Stultz
2021-11-17 5:10 ` Vinod Koul
2021-11-17 5:10 ` Vinod Koul
2021-11-17 4:49 ` Anibal Limon
2021-11-17 5:09 ` Vinod Koul
2021-11-17 5:09 ` Vinod Koul
2021-11-30 5:30 ` Vinod Koul
2021-11-30 5:30 ` Vinod Koul
2021-11-30 12:17 ` Robert Foss
2021-11-30 12:17 ` Robert Foss
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