* [PATCH v2] drm/bridge: ps8640: propagate AUX transfer register errors
@ 2026-07-23 2:38 Pengpeng Hou
2026-07-25 0:55 ` Doug Anderson
2026-07-27 11:40 ` Jani Nikula
0 siblings, 2 replies; 6+ messages in thread
From: Pengpeng Hou @ 2026-07-23 2:38 UTC (permalink / raw)
To: Douglas Anderson
Cc: Andrzej Hajda, Neil Armstrong, Robert Foss, Laurent Pinchart,
Jonas Karlman, Jernej Skrabec, Luca Ceresoli, Maarten Lankhorst,
Maxime Ripard, Thomas Zimmermann, David Airlie, Simona Vetter,
dri-devel, linux-kernel, Pengpeng Hou
ps8640_aux_transfer_msg() programs the AUX address registers, starts the
AUX transfer, waits for SWAUX_SEND to clear, and reads the AUX status
register. Several of those regmap operations have return values, but the
function only checks a stale ret after the status read.
Propagate failures from the address write, transfer start, completion
poll, and status read. This avoids returning a transfer length when the
bridge register transaction or AUX completion wait failed.
Fixes: 13afcdd7277e ("drm/bridge: parade-ps8640: Add support for AUX channel")
Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
---
Changes since v1: https://lore.kernel.org/all/20260623060635.16064-1-pengpeng@iscas.ac.cn/
- include the AUX address and length in the address-write diagnostic
- describe poll failures without assuming that every error is a timeout
- add the Fixes tag suggested by Doug
- rebase onto the current drm-misc-next tree
drivers/gpu/drm/bridge/parade-ps8640.c | 27 +++++++++++++++++++++------
1 file changed, 21 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c
index 96332721cb69..56b48f8feab6 100644
--- a/drivers/gpu/drm/bridge/parade-ps8640.c
+++ b/drivers/gpu/drm/bridge/parade-ps8640.c
@@ -257,8 +257,14 @@ static ssize_t ps8640_aux_transfer_msg(struct drm_dp_aux *aux,
addr_len[PAGE0_SWAUX_LENGTH - base] = (len == 0) ? SWAUX_NO_PAYLOAD :
((len - 1) & SWAUX_LENGTH_MASK);
- regmap_bulk_write(map, PAGE0_SWAUX_ADDR_7_0, addr_len,
- ARRAY_SIZE(addr_len));
+ ret = regmap_bulk_write(map, PAGE0_SWAUX_ADDR_7_0, addr_len,
+ ARRAY_SIZE(addr_len));
+ if (ret) {
+ DRM_DEV_ERROR(dev,
+ "failed to write AUX address %#x, len %zu: %d\n",
+ msg->address, len, ret);
+ return ret;
+ }
if (len && (request == DP_AUX_NATIVE_WRITE ||
request == DP_AUX_I2C_WRITE)) {
@@ -274,13 +280,22 @@ static ssize_t ps8640_aux_transfer_msg(struct drm_dp_aux *aux,
}
}
- regmap_write(map, PAGE0_SWAUX_CTRL, SWAUX_SEND);
+ ret = regmap_write(map, PAGE0_SWAUX_CTRL, SWAUX_SEND);
+ if (ret) {
+ DRM_DEV_ERROR(dev, "failed to start AUX transfer: %d\n", ret);
+ return ret;
+ }
/* Zero delay loop because i2c transactions are slow already */
- regmap_read_poll_timeout(map, PAGE0_SWAUX_CTRL, data,
- !(data & SWAUX_SEND), 0, 50 * 1000);
+ ret = regmap_read_poll_timeout(map, PAGE0_SWAUX_CTRL, data,
+ !(data & SWAUX_SEND), 0, 50 * 1000);
+ if (ret) {
+ DRM_DEV_ERROR(dev, "failed to complete AUX transfer: %d\n",
+ ret);
+ return ret;
+ }
- regmap_read(map, PAGE0_SWAUX_STATUS, &data);
+ ret = regmap_read(map, PAGE0_SWAUX_STATUS, &data);
if (ret) {
DRM_DEV_ERROR(dev, "failed to read PAGE0_SWAUX_STATUS: %d\n",
ret);
--
2.50.1 (Apple Git-155)
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v2] drm/bridge: ps8640: propagate AUX transfer register errors
2026-07-23 2:38 [PATCH v2] drm/bridge: ps8640: propagate AUX transfer register errors Pengpeng Hou
@ 2026-07-25 0:55 ` Doug Anderson
2026-07-27 11:40 ` Jani Nikula
1 sibling, 0 replies; 6+ messages in thread
From: Doug Anderson @ 2026-07-25 0:55 UTC (permalink / raw)
To: Pengpeng Hou
Cc: Andrzej Hajda, Neil Armstrong, Robert Foss, Laurent Pinchart,
Jonas Karlman, Jernej Skrabec, Luca Ceresoli, Maarten Lankhorst,
Maxime Ripard, Thomas Zimmermann, David Airlie, Simona Vetter,
dri-devel, linux-kernel
Hi,
On Wed, Jul 22, 2026 at 7:38 PM Pengpeng Hou <pengpeng@iscas.ac.cn> wrote:
>
> ps8640_aux_transfer_msg() programs the AUX address registers, starts the
> AUX transfer, waits for SWAUX_SEND to clear, and reads the AUX status
> register. Several of those regmap operations have return values, but the
> function only checks a stale ret after the status read.
>
> Propagate failures from the address write, transfer start, completion
> poll, and status read. This avoids returning a transfer length when the
> bridge register transaction or AUX completion wait failed.
>
> Fixes: 13afcdd7277e ("drm/bridge: parade-ps8640: Add support for AUX channel")
> Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
> ---
> Changes since v1: https://lore.kernel.org/all/20260623060635.16064-1-pengpeng@iscas.ac.cn/
> - include the AUX address and length in the address-write diagnostic
> - describe poll failures without assuming that every error is a timeout
> - add the Fixes tag suggested by Doug
> - rebase onto the current drm-misc-next tree
>
> drivers/gpu/drm/bridge/parade-ps8640.c | 27 +++++++++++++++++++++------
> 1 file changed, 21 insertions(+), 6 deletions(-)
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Assuming nothing else comes up, I'll plan to apply to drm-misc-fixes next week.
-Doug
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v2] drm/bridge: ps8640: propagate AUX transfer register errors
2026-07-23 2:38 [PATCH v2] drm/bridge: ps8640: propagate AUX transfer register errors Pengpeng Hou
2026-07-25 0:55 ` Doug Anderson
@ 2026-07-27 11:40 ` Jani Nikula
2026-07-30 1:41 ` Doug Anderson
1 sibling, 1 reply; 6+ messages in thread
From: Jani Nikula @ 2026-07-27 11:40 UTC (permalink / raw)
To: Pengpeng Hou, Douglas Anderson
Cc: Andrzej Hajda, Neil Armstrong, Robert Foss, Laurent Pinchart,
Jonas Karlman, Jernej Skrabec, Luca Ceresoli, Maarten Lankhorst,
Maxime Ripard, Thomas Zimmermann, David Airlie, Simona Vetter,
dri-devel, linux-kernel, Pengpeng Hou
On Thu, 23 Jul 2026, Pengpeng Hou <pengpeng@iscas.ac.cn> wrote:
> ps8640_aux_transfer_msg() programs the AUX address registers, starts the
> AUX transfer, waits for SWAUX_SEND to clear, and reads the AUX status
> register. Several of those regmap operations have return values, but the
> function only checks a stale ret after the status read.
>
> Propagate failures from the address write, transfer start, completion
> poll, and status read. This avoids returning a transfer length when the
> bridge register transaction or AUX completion wait failed.
>
> Fixes: 13afcdd7277e ("drm/bridge: parade-ps8640: Add support for AUX channel")
> Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
> ---
> Changes since v1: https://lore.kernel.org/all/20260623060635.16064-1-pengpeng@iscas.ac.cn/
> - include the AUX address and length in the address-write diagnostic
> - describe poll failures without assuming that every error is a timeout
> - add the Fixes tag suggested by Doug
> - rebase onto the current drm-misc-next tree
>
> drivers/gpu/drm/bridge/parade-ps8640.c | 27 +++++++++++++++++++++------
> 1 file changed, 21 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c
> index 96332721cb69..56b48f8feab6 100644
> --- a/drivers/gpu/drm/bridge/parade-ps8640.c
> +++ b/drivers/gpu/drm/bridge/parade-ps8640.c
> @@ -257,8 +257,14 @@ static ssize_t ps8640_aux_transfer_msg(struct drm_dp_aux *aux,
> addr_len[PAGE0_SWAUX_LENGTH - base] = (len == 0) ? SWAUX_NO_PAYLOAD :
> ((len - 1) & SWAUX_LENGTH_MASK);
>
> - regmap_bulk_write(map, PAGE0_SWAUX_ADDR_7_0, addr_len,
> - ARRAY_SIZE(addr_len));
> + ret = regmap_bulk_write(map, PAGE0_SWAUX_ADDR_7_0, addr_len,
> + ARRAY_SIZE(addr_len));
> + if (ret) {
> + DRM_DEV_ERROR(dev,
DRM_DEV_ERROR() is deprecated in favour of drm_err() or dev_err().
BR,
Jani.
> + "failed to write AUX address %#x, len %zu: %d\n",
> + msg->address, len, ret);
> + return ret;
> + }
>
> if (len && (request == DP_AUX_NATIVE_WRITE ||
> request == DP_AUX_I2C_WRITE)) {
> @@ -274,13 +280,22 @@ static ssize_t ps8640_aux_transfer_msg(struct drm_dp_aux *aux,
> }
> }
>
> - regmap_write(map, PAGE0_SWAUX_CTRL, SWAUX_SEND);
> + ret = regmap_write(map, PAGE0_SWAUX_CTRL, SWAUX_SEND);
> + if (ret) {
> + DRM_DEV_ERROR(dev, "failed to start AUX transfer: %d\n", ret);
> + return ret;
> + }
>
> /* Zero delay loop because i2c transactions are slow already */
> - regmap_read_poll_timeout(map, PAGE0_SWAUX_CTRL, data,
> - !(data & SWAUX_SEND), 0, 50 * 1000);
> + ret = regmap_read_poll_timeout(map, PAGE0_SWAUX_CTRL, data,
> + !(data & SWAUX_SEND), 0, 50 * 1000);
> + if (ret) {
> + DRM_DEV_ERROR(dev, "failed to complete AUX transfer: %d\n",
> + ret);
> + return ret;
> + }
>
> - regmap_read(map, PAGE0_SWAUX_STATUS, &data);
> + ret = regmap_read(map, PAGE0_SWAUX_STATUS, &data);
> if (ret) {
> DRM_DEV_ERROR(dev, "failed to read PAGE0_SWAUX_STATUS: %d\n",
> ret);
--
Jani Nikula, Intel
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v2] drm/bridge: ps8640: propagate AUX transfer register errors
2026-07-27 11:40 ` Jani Nikula
@ 2026-07-30 1:41 ` Doug Anderson
2026-07-30 8:38 ` Jani Nikula
0 siblings, 1 reply; 6+ messages in thread
From: Doug Anderson @ 2026-07-30 1:41 UTC (permalink / raw)
To: Jani Nikula
Cc: Pengpeng Hou, Andrzej Hajda, Neil Armstrong, Robert Foss,
Laurent Pinchart, Jonas Karlman, Jernej Skrabec, Luca Ceresoli,
Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
David Airlie, Simona Vetter, dri-devel, linux-kernel
Hi,
On Mon, Jul 27, 2026 at 4:40 AM Jani Nikula <jani.nikula@linux.intel.com> wrote:
>
> On Thu, 23 Jul 2026, Pengpeng Hou <pengpeng@iscas.ac.cn> wrote:
> > ps8640_aux_transfer_msg() programs the AUX address registers, starts the
> > AUX transfer, waits for SWAUX_SEND to clear, and reads the AUX status
> > register. Several of those regmap operations have return values, but the
> > function only checks a stale ret after the status read.
> >
> > Propagate failures from the address write, transfer start, completion
> > poll, and status read. This avoids returning a transfer length when the
> > bridge register transaction or AUX completion wait failed.
> >
> > Fixes: 13afcdd7277e ("drm/bridge: parade-ps8640: Add support for AUX channel")
> > Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
> > ---
> > Changes since v1: https://lore.kernel.org/all/20260623060635.16064-1-pengpeng@iscas.ac.cn/
> > - include the AUX address and length in the address-write diagnostic
> > - describe poll failures without assuming that every error is a timeout
> > - add the Fixes tag suggested by Doug
> > - rebase onto the current drm-misc-next tree
> >
> > drivers/gpu/drm/bridge/parade-ps8640.c | 27 +++++++++++++++++++++------
> > 1 file changed, 21 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c
> > index 96332721cb69..56b48f8feab6 100644
> > --- a/drivers/gpu/drm/bridge/parade-ps8640.c
> > +++ b/drivers/gpu/drm/bridge/parade-ps8640.c
> > @@ -257,8 +257,14 @@ static ssize_t ps8640_aux_transfer_msg(struct drm_dp_aux *aux,
> > addr_len[PAGE0_SWAUX_LENGTH - base] = (len == 0) ? SWAUX_NO_PAYLOAD :
> > ((len - 1) & SWAUX_LENGTH_MASK);
> >
> > - regmap_bulk_write(map, PAGE0_SWAUX_ADDR_7_0, addr_len,
> > - ARRAY_SIZE(addr_len));
> > + ret = regmap_bulk_write(map, PAGE0_SWAUX_ADDR_7_0, addr_len,
> > + ARRAY_SIZE(addr_len));
> > + if (ret) {
> > + DRM_DEV_ERROR(dev,
>
> DRM_DEV_ERROR() is deprecated in favour of drm_err() or dev_err().
Good point. I'm inclined to land this anyway, though, since this is
nominally a bugfix and it matches the error printing in the rest of
the function. Any objections? It would be a nice future cleanup to fix
the error printing in this driver overall to use the non-deprecated
functions...
-Doug
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v2] drm/bridge: ps8640: propagate AUX transfer register errors
2026-07-30 1:41 ` Doug Anderson
@ 2026-07-30 8:38 ` Jani Nikula
2026-07-30 21:26 ` Doug Anderson
0 siblings, 1 reply; 6+ messages in thread
From: Jani Nikula @ 2026-07-30 8:38 UTC (permalink / raw)
To: Doug Anderson
Cc: Pengpeng Hou, Andrzej Hajda, Neil Armstrong, Robert Foss,
Laurent Pinchart, Jonas Karlman, Jernej Skrabec, Luca Ceresoli,
Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
David Airlie, Simona Vetter, dri-devel, linux-kernel
On Wed, 29 Jul 2026, Doug Anderson <dianders@chromium.org> wrote:
> Hi,
>
> On Mon, Jul 27, 2026 at 4:40 AM Jani Nikula <jani.nikula@linux.intel.com> wrote:
>>
>> On Thu, 23 Jul 2026, Pengpeng Hou <pengpeng@iscas.ac.cn> wrote:
>> > ps8640_aux_transfer_msg() programs the AUX address registers, starts the
>> > AUX transfer, waits for SWAUX_SEND to clear, and reads the AUX status
>> > register. Several of those regmap operations have return values, but the
>> > function only checks a stale ret after the status read.
>> >
>> > Propagate failures from the address write, transfer start, completion
>> > poll, and status read. This avoids returning a transfer length when the
>> > bridge register transaction or AUX completion wait failed.
>> >
>> > Fixes: 13afcdd7277e ("drm/bridge: parade-ps8640: Add support for AUX channel")
>> > Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
>> > ---
>> > Changes since v1: https://lore.kernel.org/all/20260623060635.16064-1-pengpeng@iscas.ac.cn/
>> > - include the AUX address and length in the address-write diagnostic
>> > - describe poll failures without assuming that every error is a timeout
>> > - add the Fixes tag suggested by Doug
>> > - rebase onto the current drm-misc-next tree
>> >
>> > drivers/gpu/drm/bridge/parade-ps8640.c | 27 +++++++++++++++++++++------
>> > 1 file changed, 21 insertions(+), 6 deletions(-)
>> >
>> > diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c
>> > index 96332721cb69..56b48f8feab6 100644
>> > --- a/drivers/gpu/drm/bridge/parade-ps8640.c
>> > +++ b/drivers/gpu/drm/bridge/parade-ps8640.c
>> > @@ -257,8 +257,14 @@ static ssize_t ps8640_aux_transfer_msg(struct drm_dp_aux *aux,
>> > addr_len[PAGE0_SWAUX_LENGTH - base] = (len == 0) ? SWAUX_NO_PAYLOAD :
>> > ((len - 1) & SWAUX_LENGTH_MASK);
>> >
>> > - regmap_bulk_write(map, PAGE0_SWAUX_ADDR_7_0, addr_len,
>> > - ARRAY_SIZE(addr_len));
>> > + ret = regmap_bulk_write(map, PAGE0_SWAUX_ADDR_7_0, addr_len,
>> > + ARRAY_SIZE(addr_len));
>> > + if (ret) {
>> > + DRM_DEV_ERROR(dev,
>>
>> DRM_DEV_ERROR() is deprecated in favour of drm_err() or dev_err().
>
> Good point. I'm inclined to land this anyway, though, since this is
> nominally a bugfix and it matches the error printing in the rest of
> the function. Any objections? It would be a nice future cleanup to fix
> the error printing in this driver overall to use the non-deprecated
> functions...
Up to you.
BR,
Jani.
--
Jani Nikula, Intel
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v2] drm/bridge: ps8640: propagate AUX transfer register errors
2026-07-30 8:38 ` Jani Nikula
@ 2026-07-30 21:26 ` Doug Anderson
0 siblings, 0 replies; 6+ messages in thread
From: Doug Anderson @ 2026-07-30 21:26 UTC (permalink / raw)
To: Jani Nikula
Cc: Pengpeng Hou, Andrzej Hajda, Neil Armstrong, Robert Foss,
Laurent Pinchart, Jonas Karlman, Jernej Skrabec, Luca Ceresoli,
Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
David Airlie, Simona Vetter, dri-devel, linux-kernel
Hi,
On Thu, Jul 30, 2026 at 1:38 AM Jani Nikula <jani.nikula@linux.intel.com> wrote:
>
> On Wed, 29 Jul 2026, Doug Anderson <dianders@chromium.org> wrote:
> > Hi,
> >
> > On Mon, Jul 27, 2026 at 4:40 AM Jani Nikula <jani.nikula@linux.intel.com> wrote:
> >>
> >> On Thu, 23 Jul 2026, Pengpeng Hou <pengpeng@iscas.ac.cn> wrote:
> >> > ps8640_aux_transfer_msg() programs the AUX address registers, starts the
> >> > AUX transfer, waits for SWAUX_SEND to clear, and reads the AUX status
> >> > register. Several of those regmap operations have return values, but the
> >> > function only checks a stale ret after the status read.
> >> >
> >> > Propagate failures from the address write, transfer start, completion
> >> > poll, and status read. This avoids returning a transfer length when the
> >> > bridge register transaction or AUX completion wait failed.
> >> >
> >> > Fixes: 13afcdd7277e ("drm/bridge: parade-ps8640: Add support for AUX channel")
> >> > Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
> >> > ---
> >> > Changes since v1: https://lore.kernel.org/all/20260623060635.16064-1-pengpeng@iscas.ac.cn/
> >> > - include the AUX address and length in the address-write diagnostic
> >> > - describe poll failures without assuming that every error is a timeout
> >> > - add the Fixes tag suggested by Doug
> >> > - rebase onto the current drm-misc-next tree
> >> >
> >> > drivers/gpu/drm/bridge/parade-ps8640.c | 27 +++++++++++++++++++++------
> >> > 1 file changed, 21 insertions(+), 6 deletions(-)
> >> >
> >> > diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c
> >> > index 96332721cb69..56b48f8feab6 100644
> >> > --- a/drivers/gpu/drm/bridge/parade-ps8640.c
> >> > +++ b/drivers/gpu/drm/bridge/parade-ps8640.c
> >> > @@ -257,8 +257,14 @@ static ssize_t ps8640_aux_transfer_msg(struct drm_dp_aux *aux,
> >> > addr_len[PAGE0_SWAUX_LENGTH - base] = (len == 0) ? SWAUX_NO_PAYLOAD :
> >> > ((len - 1) & SWAUX_LENGTH_MASK);
> >> >
> >> > - regmap_bulk_write(map, PAGE0_SWAUX_ADDR_7_0, addr_len,
> >> > - ARRAY_SIZE(addr_len));
> >> > + ret = regmap_bulk_write(map, PAGE0_SWAUX_ADDR_7_0, addr_len,
> >> > + ARRAY_SIZE(addr_len));
> >> > + if (ret) {
> >> > + DRM_DEV_ERROR(dev,
> >>
> >> DRM_DEV_ERROR() is deprecated in favour of drm_err() or dev_err().
> >
> > Good point. I'm inclined to land this anyway, though, since this is
> > nominally a bugfix and it matches the error printing in the rest of
> > the function. Any objections? It would be a nice future cleanup to fix
> > the error printing in this driver overall to use the non-deprecated
> > functions...
>
> Up to you.
OK, pushed to drm-misc-fixes.
[1/1] drm/bridge: ps8640: propagate AUX transfer register errors
commit: 20697ecb299cd77b4cf8b28f655e56606b0472d8
It would be great if someone wanted to update the error prints. :-)
-Doug
^ permalink raw reply [flat|nested] 6+ messages in thread
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2026-07-23 2:38 [PATCH v2] drm/bridge: ps8640: propagate AUX transfer register errors Pengpeng Hou
2026-07-25 0:55 ` Doug Anderson
2026-07-27 11:40 ` Jani Nikula
2026-07-30 1:41 ` Doug Anderson
2026-07-30 8:38 ` Jani Nikula
2026-07-30 21:26 ` Doug Anderson
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