Re: v4l2-async: regression due to endpoint matching

Re: v4l2-async: regression due to endpoint matching

[Linux regression tracking #adding (Thorsten Leemhuis)]

[CCing the regression list, as it should be in the loop for regressions:
https://docs.kernel.org/admin-guide/reporting-regressions.html]

[TLDR: I'm adding this report to the list of tracked Linux kernel
regressions; the text you find below is based on a few templates
paragraphs you might have encountered already in similar form.
See link in footer if these mails annoy you.]

On 27.04.23 16:40, Alexander Stein wrote:
> 
> I have a setup on my TQMa6x (imx6q-mba6a.dts) with a tc358743 attached to the 
> MIPI CSI input.
> I noticed that since commit 1f391df44607 ("media: v4l2-async: Use endpoints in 
> __v4l2_async_nf_add_fwnode_remote()") the async subdevice probing does not 
> work anymore. If I revert that, it is working again, even on next-20230425.
> [...]

Thanks for the report. To be sure the issue doesn't fall through the
cracks unnoticed, I'm adding it to regzbot, the Linux kernel regression
tracking bot:

#regzbot ^introduced 1f391df44607
#regzbot title media: v4l2-async: async subdevice probing stopped
working on TQMa6x
#regzbot ignore-activity

This isn't a regression? This issue or a fix for it are already
discussed somewhere else? It was fixed already? You want to clarify when
the regression started to happen? Or point out I got the title or
something else totally wrong? Then just reply and tell me -- ideally
while also telling regzbot about it, as explained by the page listed in
the footer of this mail.

Developers: When fixing the issue, remember to add 'Link:' tags pointing
to the report (the parent of this mail). See page linked in footer for
details.

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
--
Everything you wanna know about Linux kernel regression tracking:
https://linux-regtracking.leemhuis.info/about/#tldr
That page also explains what to do if mails like this annoy you.

Re: v4l2-async: regression due to endpoint matching

[Linux regression tracking (Thorsten Leemhuis)]

On 28.04.23 09:16, Sakari Ailus wrote:
> On Fri, Apr 28, 2023 at 08:43:21AM +0200, Jacopo Mondi wrote:
>> On Fri, Apr 28, 2023 at 08:33:30AM +0200, Alexander Stein wrote:
>>> Am Freitag, 28. April 2023, 08:31:54 CEST schrieb Jacopo Mondi:
>>>> On Fri, Apr 28, 2023 at 08:24:22AM +0200, Alexander Stein wrote:
>>>>> Am Donnerstag, 27. April 2023, 18:01:38 CEST schrieb Jacopo Mondi:
>>>>>> On Thu, Apr 27, 2023 at 04:40:46PM +0200, Alexander Stein wrote:
>>>>>>> I have a setup on my TQMa6x (imx6q-mba6a.dts) with a tc358743 attached
>>>>>>> to
>>>>>>> the MIPI CSI input.
>>>>>>> I noticed that since commit 1f391df44607 ("media: v4l2-async: Use
>>>>>>> endpoints in __v4l2_async_nf_add_fwnode_remote()") the async subdevice
>>>>>>> probing does not work anymore. If I revert that, it is working again,
>>>>>>> even on next-20230425.
>>>>>>
>>>>>> A similar issue has been discussed at
>>>>>> https://www.spinics.net/lists/linux-media/msg223351.html
>>>>>>
>>>>>> Unfortunately there was no conclusion as far as I can tell if not that
>>>>>> imx6 is now broken
>>>>>
>>>>> Thanks for the link, seems like a non-trivial thing :(
>>>>>
>>>>> From a glimpse, this series seems to deal with multiple async subdevs:
>>>>> https://lore.kernel.org/all/20230330115853.1628216-1-sakari.ailus@linux.in
>>>>> tel.com/
>>>>>
>>>>> So imx-media-csi should be adjusted as well, no?
>>>>
>>>> It would really be helpful if you can give that series a spin on imx6
>>>> if you already have a test setup.
>>>
>>> I tried, but it failed to apply on my current development tree. What base does
>>> this series apply to? Is there also a repository available I can fetch from?
>>
>> Sakari could tell, for me it applied on v6.3-rc2 but I recall I had to
>> manually fix a few things.
> 
> Don't try v1, it won't work. I missed some object relation changes in the
> linked lists. I'll post v2, hopefully some time next week, to address these
> issues.

Hi, Thorsten here, the Linux kernel's regression tracker.

I see that v2[1] got a lot of ACKs, but is not even yet in next. And
it's a lot of patches, so maybe too much for backporting to stable
kernels. Which leads to the question: Will the regression this thread is
about (introduced in 5.19 afaics) ever be fixed in v6.1?
Normally/Ideally it should be.

Ciao, Thorsten

[1]
https://lore.kernel.org/linux-media/ZEtytxcB2+DA8Xs%2F@kekkonen.localdomain/

Re: v4l2-async: regression due to endpoint matching

[Sakari Ailus]

Hi Thorsten,

On Mon, May 22, 2023 at 12:53:52PM +0200, Linux regression tracking (Thorsten Leemhuis) wrote:
> On 28.04.23 09:16, Sakari Ailus wrote:
> > On Fri, Apr 28, 2023 at 08:43:21AM +0200, Jacopo Mondi wrote:
> >> On Fri, Apr 28, 2023 at 08:33:30AM +0200, Alexander Stein wrote:
> >>> Am Freitag, 28. April 2023, 08:31:54 CEST schrieb Jacopo Mondi:
> >>>> On Fri, Apr 28, 2023 at 08:24:22AM +0200, Alexander Stein wrote:
> >>>>> Am Donnerstag, 27. April 2023, 18:01:38 CEST schrieb Jacopo Mondi:
> >>>>>> On Thu, Apr 27, 2023 at 04:40:46PM +0200, Alexander Stein wrote:
> >>>>>>> I have a setup on my TQMa6x (imx6q-mba6a.dts) with a tc358743 attached
> >>>>>>> to
> >>>>>>> the MIPI CSI input.
> >>>>>>> I noticed that since commit 1f391df44607 ("media: v4l2-async: Use
> >>>>>>> endpoints in __v4l2_async_nf_add_fwnode_remote()") the async subdevice
> >>>>>>> probing does not work anymore. If I revert that, it is working again,
> >>>>>>> even on next-20230425.
> >>>>>>
> >>>>>> A similar issue has been discussed at
> >>>>>> https://www.spinics.net/lists/linux-media/msg223351.html
> >>>>>>
> >>>>>> Unfortunately there was no conclusion as far as I can tell if not that
> >>>>>> imx6 is now broken
> >>>>>
> >>>>> Thanks for the link, seems like a non-trivial thing :(
> >>>>>
> >>>>> From a glimpse, this series seems to deal with multiple async subdevs:
> >>>>> https://lore.kernel.org/all/20230330115853.1628216-1-sakari.ailus@linux.in
> >>>>> tel.com/
> >>>>>
> >>>>> So imx-media-csi should be adjusted as well, no?
> >>>>
> >>>> It would really be helpful if you can give that series a spin on imx6
> >>>> if you already have a test setup.
> >>>
> >>> I tried, but it failed to apply on my current development tree. What base does
> >>> this series apply to? Is there also a repository available I can fetch from?
> >>
> >> Sakari could tell, for me it applied on v6.3-rc2 but I recall I had to
> >> manually fix a few things.
> > 
> > Don't try v1, it won't work. I missed some object relation changes in the
> > linked lists. I'll post v2, hopefully some time next week, to address these
> > issues.
> 
> Hi, Thorsten here, the Linux kernel's regression tracker.
> 
> I see that v2[1] got a lot of ACKs, but is not even yet in next. And
> it's a lot of patches, so maybe too much for backporting to stable
> kernels. Which leads to the question: Will the regression this thread is
> about (introduced in 5.19 afaics) ever be fixed in v6.1?
> Normally/Ideally it should be.

We'll need v3 (at least), a problem that's not trivial to fix was
identified with v2. There patches aren't really fixes either: it's new
functionality that wasn't there previously. I.MX6 just happened to work due
to missing checks in the V4L2 async framework, what it needs was never
supported (without this set).

Dropping endpoint matching will break adv748x driver that relies on it.

So I'd expect i.MX6 to work again once we have this set in, but I wouldn't
try to backport the set.

Cc Niklas.

-- 
Regards,

Sakari Ailus

Re: v4l2-async: regression due to endpoint matching

[Linux regression tracking (Thorsten Leemhuis)]

On 22.05.23 13:59, Sakari Ailus wrote:
> On Mon, May 22, 2023 at 12:53:52PM +0200, Linux regression tracking (Thorsten Leemhuis) wrote:
>> On 28.04.23 09:16, Sakari Ailus wrote:
>>> On Fri, Apr 28, 2023 at 08:43:21AM +0200, Jacopo Mondi wrote:
>>>> On Fri, Apr 28, 2023 at 08:33:30AM +0200, Alexander Stein wrote:
>>>>> Am Freitag, 28. April 2023, 08:31:54 CEST schrieb Jacopo Mondi:
>>>>>> On Fri, Apr 28, 2023 at 08:24:22AM +0200, Alexander Stein wrote:
>>>>>>> Am Donnerstag, 27. April 2023, 18:01:38 CEST schrieb Jacopo Mondi:
>>>>>>>> On Thu, Apr 27, 2023 at 04:40:46PM +0200, Alexander Stein wrote:
>>>>>>>>> I have a setup on my TQMa6x (imx6q-mba6a.dts) with a tc358743 attached
>>>>>>>>> to
>>>>>>>>> the MIPI CSI input.
>>>>>>>>> I noticed that since commit 1f391df44607 ("media: v4l2-async: Use
>>>>>>>>> endpoints in __v4l2_async_nf_add_fwnode_remote()") the async subdevice
>>>>>>>>> probing does not work anymore. If I revert that, it is working again,
>>>>>>>>> even on next-20230425.
>>>>>>>>
>>>>>>>> A similar issue has been discussed at
>>>>>>>> https://www.spinics.net/lists/linux-media/msg223351.html
>>>>>>>>
>>>>>>>> Unfortunately there was no conclusion as far as I can tell if not that
>>>>>>>> imx6 is now broken
>>>>>>>
>>>>>>> Thanks for the link, seems like a non-trivial thing :(
>>>>>>>
>>>>>>> From a glimpse, this series seems to deal with multiple async subdevs:
>>>>>>> https://lore.kernel.org/all/20230330115853.1628216-1-sakari.ailus@linux.in
>>>>>>> tel.com/
>>>>>>>
>>>>>>> So imx-media-csi should be adjusted as well, no?
>>>>>>
>>>>>> It would really be helpful if you can give that series a spin on imx6
>>>>>> if you already have a test setup.
>>>>>
>>>>> I tried, but it failed to apply on my current development tree. What base does
>>>>> this series apply to? Is there also a repository available I can fetch from?
>>>>
>>>> Sakari could tell, for me it applied on v6.3-rc2 but I recall I had to
>>>> manually fix a few things.
>>>
>>> Don't try v1, it won't work. I missed some object relation changes in the
>>> linked lists. I'll post v2, hopefully some time next week, to address these
>>> issues.
>>
>> Hi, Thorsten here, the Linux kernel's regression tracker.
>>
>> I see that v2[1] got a lot of ACKs, but is not even yet in next. And
>> it's a lot of patches, so maybe too much for backporting to stable
>> kernels. Which leads to the question: Will the regression this thread is
>> about (introduced in 5.19 afaics) ever be fixed in v6.1?
>> Normally/Ideally it should be.
> 
> We'll need v3 (at least), a problem that's not trivial to fix was
> identified with v2. There patches aren't really fixes either: it's new
> functionality that wasn't there previously. I.MX6 just happened to work due
> to missing checks in the V4L2 async framework, what it needs was never
> supported (without this set).
> 
> Dropping endpoint matching will break adv748x driver that relies on it.
> 
> So I'd expect i.MX6 to work again once we have this set in, but I wouldn't
> try to backport the set.

Thx for the update. Makes me wonder if reverting the culprit[1] is an
option. Assuming the problem still happens. Alexander, is that the case?

Ciao, Thorsten

[1] 1f391df4460 ("media: v4l2-async: Use endpoints in
__v4l2_async_nf_add_fwnode_remote()") (v5.19-rc1; authored by Laurent,
commited by Mauro (both now CCed))

Re: v4l2-async: regression due to endpoint matching

[Sakari Ailus]

Hi Thorsten,

On Mon, May 22, 2023 at 02:11:29PM +0200, Linux regression tracking (Thorsten Leemhuis) wrote:
> On 22.05.23 13:59, Sakari Ailus wrote:
> > On Mon, May 22, 2023 at 12:53:52PM +0200, Linux regression tracking (Thorsten Leemhuis) wrote:
> >> On 28.04.23 09:16, Sakari Ailus wrote:
> >>> On Fri, Apr 28, 2023 at 08:43:21AM +0200, Jacopo Mondi wrote:
> >>>> On Fri, Apr 28, 2023 at 08:33:30AM +0200, Alexander Stein wrote:
> >>>>> Am Freitag, 28. April 2023, 08:31:54 CEST schrieb Jacopo Mondi:
> >>>>>> On Fri, Apr 28, 2023 at 08:24:22AM +0200, Alexander Stein wrote:
> >>>>>>> Am Donnerstag, 27. April 2023, 18:01:38 CEST schrieb Jacopo Mondi:
> >>>>>>>> On Thu, Apr 27, 2023 at 04:40:46PM +0200, Alexander Stein wrote:
> >>>>>>>>> I have a setup on my TQMa6x (imx6q-mba6a.dts) with a tc358743 attached
> >>>>>>>>> to
> >>>>>>>>> the MIPI CSI input.
> >>>>>>>>> I noticed that since commit 1f391df44607 ("media: v4l2-async: Use
> >>>>>>>>> endpoints in __v4l2_async_nf_add_fwnode_remote()") the async subdevice
> >>>>>>>>> probing does not work anymore. If I revert that, it is working again,
> >>>>>>>>> even on next-20230425.
> >>>>>>>>
> >>>>>>>> A similar issue has been discussed at
> >>>>>>>> https://www.spinics.net/lists/linux-media/msg223351.html
> >>>>>>>>
> >>>>>>>> Unfortunately there was no conclusion as far as I can tell if not that
> >>>>>>>> imx6 is now broken
> >>>>>>>
> >>>>>>> Thanks for the link, seems like a non-trivial thing :(
> >>>>>>>
> >>>>>>> From a glimpse, this series seems to deal with multiple async subdevs:
> >>>>>>> https://lore.kernel.org/all/20230330115853.1628216-1-sakari.ailus@linux.in
> >>>>>>> tel.com/
> >>>>>>>
> >>>>>>> So imx-media-csi should be adjusted as well, no?
> >>>>>>
> >>>>>> It would really be helpful if you can give that series a spin on imx6
> >>>>>> if you already have a test setup.
> >>>>>
> >>>>> I tried, but it failed to apply on my current development tree. What base does
> >>>>> this series apply to? Is there also a repository available I can fetch from?
> >>>>
> >>>> Sakari could tell, for me it applied on v6.3-rc2 but I recall I had to
> >>>> manually fix a few things.
> >>>
> >>> Don't try v1, it won't work. I missed some object relation changes in the
> >>> linked lists. I'll post v2, hopefully some time next week, to address these
> >>> issues.
> >>
> >> Hi, Thorsten here, the Linux kernel's regression tracker.
> >>
> >> I see that v2[1] got a lot of ACKs, but is not even yet in next. And
> >> it's a lot of patches, so maybe too much for backporting to stable
> >> kernels. Which leads to the question: Will the regression this thread is
> >> about (introduced in 5.19 afaics) ever be fixed in v6.1?
> >> Normally/Ideally it should be.
> > 
> > We'll need v3 (at least), a problem that's not trivial to fix was
> > identified with v2. There patches aren't really fixes either: it's new
> > functionality that wasn't there previously. I.MX6 just happened to work due
> > to missing checks in the V4L2 async framework, what it needs was never
> > supported (without this set).
> > 
> > Dropping endpoint matching will break adv748x driver that relies on it.
> > 
> > So I'd expect i.MX6 to work again once we have this set in, but I wouldn't
> > try to backport the set.
> 
> Thx for the update. Makes me wonder if reverting the culprit[1] is an
> option. Assuming the problem still happens. Alexander, is that the case?
> 
> Ciao, Thorsten
> 
> [1] 1f391df4460 ("media: v4l2-async: Use endpoints in
> __v4l2_async_nf_add_fwnode_remote()") (v5.19-rc1; authored by Laurent,
> commited by Mauro (both now CCed))

I prioritise an in-kernel driver over a staging driver.

-- 
Regards,

Sakari Ailus

Re: v4l2-async: regression due to endpoint matching

[Thorsten Leemhuis]

On 22.05.23 14:51, Sakari Ailus wrote:
> On Mon, May 22, 2023 at 02:11:29PM +0200, Linux regression tracking (Thorsten Leemhuis) wrote:
>> On 22.05.23 13:59, Sakari Ailus wrote:
>>> On Mon, May 22, 2023 at 12:53:52PM +0200, Linux regression tracking (Thorsten Leemhuis) wrote:
>>>> On 28.04.23 09:16, Sakari Ailus wrote:
>>>>> On Fri, Apr 28, 2023 at 08:43:21AM +0200, Jacopo Mondi wrote:
>>>>>> On Fri, Apr 28, 2023 at 08:33:30AM +0200, Alexander Stein wrote:
>>>>>>> Am Freitag, 28. April 2023, 08:31:54 CEST schrieb Jacopo Mondi:
>>>>>>>> On Fri, Apr 28, 2023 at 08:24:22AM +0200, Alexander Stein wrote:
>>>>>>>>> Am Donnerstag, 27. April 2023, 18:01:38 CEST schrieb Jacopo Mondi:
>>>>>>>>>> On Thu, Apr 27, 2023 at 04:40:46PM +0200, Alexander Stein wrote:
>>>>>>>>>>> I have a setup on my TQMa6x (imx6q-mba6a.dts) with a tc358743 attached
>>>>>>>>>>> to
>>>>>>>>>>> the MIPI CSI input.
>>>>>>>>>>> I noticed that since commit 1f391df44607 ("media: v4l2-async: Use
>>>>>>>>>>> endpoints in __v4l2_async_nf_add_fwnode_remote()") the async subdevice
>>>>>>>>>>> probing does not work anymore. If I revert that, it is working again,
>>>>>>>>>>> even on next-20230425.
>>>>>>>>>>
>>>>>>>>>> A similar issue has been discussed at
>>>>>>>>>> https://www.spinics.net/lists/linux-media/msg223351.html
>>>>>>>>>>
>>>>>>>>>> Unfortunately there was no conclusion as far as I can tell if not that
>>>>>>>>>> imx6 is now broken
>>>>>>>>>
>>>>>>>>> Thanks for the link, seems like a non-trivial thing :(
>>>>>>>>>
>>>>>>>>> From a glimpse, this series seems to deal with multiple async subdevs:
>>>>>>>>> https://lore.kernel.org/all/20230330115853.1628216-1-sakari.ailus@linux.in
>>>>>>>>> tel.com/
>>>>>>>>>
>>>>>>>>> So imx-media-csi should be adjusted as well, no?
>>>>>>>>
>>>>>>>> It would really be helpful if you can give that series a spin on imx6
>>>>>>>> if you already have a test setup.
>>>>>>>
>>>>>>> I tried, but it failed to apply on my current development tree. What base does
>>>>>>> this series apply to? Is there also a repository available I can fetch from?
>>>>>>
>>>>>> Sakari could tell, for me it applied on v6.3-rc2 but I recall I had to
>>>>>> manually fix a few things.
>>>>>
>>>>> Don't try v1, it won't work. I missed some object relation changes in the
>>>>> linked lists. I'll post v2, hopefully some time next week, to address these
>>>>> issues.
>>>>
>>>> Hi, Thorsten here, the Linux kernel's regression tracker.
>>>>
>>>> I see that v2[1] got a lot of ACKs, but is not even yet in next. And
>>>> it's a lot of patches, so maybe too much for backporting to stable
>>>> kernels. Which leads to the question: Will the regression this thread is
>>>> about (introduced in 5.19 afaics) ever be fixed in v6.1?
>>>> Normally/Ideally it should be.
>>>
>>> We'll need v3 (at least), a problem that's not trivial to fix was
>>> identified with v2. There patches aren't really fixes either: it's new
>>> functionality that wasn't there previously. I.MX6 just happened to work due
>>> to missing checks in the V4L2 async framework, what it needs was never
>>> supported (without this set).
>>>
>>> Dropping endpoint matching will break adv748x driver that relies on it.
>>>
>>> So I'd expect i.MX6 to work again once we have this set in, but I wouldn't
>>> try to backport the set.
>>
>> Thx for the update. Makes me wonder if reverting the culprit[1] is an
>> option. Assuming the problem still happens. Alexander, is that the case?
>>
>> Ciao, Thorsten
>>
>> [1] 1f391df4460 ("media: v4l2-async: Use endpoints in
>> __v4l2_async_nf_add_fwnode_remote()") (v5.19-rc1; authored by Laurent,
>> commited by Mauro (both now CCed))
> 
> I prioritise an in-kernel driver over a staging driver.

Sorry, can't follow. I track regressions all over the kernel and try to
follow the best I can, but here I failed, as I have no idea which
staging driver I mean.

I see a regression that is not really addressed and I wonder if there is
a way to fix this until a proper solution is ready. Usually in this
cases the culprit is reverted, unless that itself would cause another
regression. Is that the case here? It sounds a bit like it, but would be
great if somebody could confirm that.

Ciao, Thorsten

Re: v4l2-async: regression due to endpoint matching

[Sakari Ailus]

On Wed, May 24, 2023 at 01:52:14PM +0200, Thorsten Leemhuis wrote:
> On 22.05.23 14:51, Sakari Ailus wrote:
> > On Mon, May 22, 2023 at 02:11:29PM +0200, Linux regression tracking (Thorsten Leemhuis) wrote:
> >> On 22.05.23 13:59, Sakari Ailus wrote:
> >>> On Mon, May 22, 2023 at 12:53:52PM +0200, Linux regression tracking (Thorsten Leemhuis) wrote:
> >>>> On 28.04.23 09:16, Sakari Ailus wrote:
> >>>>> On Fri, Apr 28, 2023 at 08:43:21AM +0200, Jacopo Mondi wrote:
> >>>>>> On Fri, Apr 28, 2023 at 08:33:30AM +0200, Alexander Stein wrote:
> >>>>>>> Am Freitag, 28. April 2023, 08:31:54 CEST schrieb Jacopo Mondi:
> >>>>>>>> On Fri, Apr 28, 2023 at 08:24:22AM +0200, Alexander Stein wrote:
> >>>>>>>>> Am Donnerstag, 27. April 2023, 18:01:38 CEST schrieb Jacopo Mondi:
> >>>>>>>>>> On Thu, Apr 27, 2023 at 04:40:46PM +0200, Alexander Stein wrote:
> >>>>>>>>>>> I have a setup on my TQMa6x (imx6q-mba6a.dts) with a tc358743 attached
> >>>>>>>>>>> to
> >>>>>>>>>>> the MIPI CSI input.
> >>>>>>>>>>> I noticed that since commit 1f391df44607 ("media: v4l2-async: Use
> >>>>>>>>>>> endpoints in __v4l2_async_nf_add_fwnode_remote()") the async subdevice
> >>>>>>>>>>> probing does not work anymore. If I revert that, it is working again,
> >>>>>>>>>>> even on next-20230425.
> >>>>>>>>>>
> >>>>>>>>>> A similar issue has been discussed at
> >>>>>>>>>> https://www.spinics.net/lists/linux-media/msg223351.html
> >>>>>>>>>>
> >>>>>>>>>> Unfortunately there was no conclusion as far as I can tell if not that
> >>>>>>>>>> imx6 is now broken
> >>>>>>>>>
> >>>>>>>>> Thanks for the link, seems like a non-trivial thing :(
> >>>>>>>>>
> >>>>>>>>> From a glimpse, this series seems to deal with multiple async subdevs:
> >>>>>>>>> https://lore.kernel.org/all/20230330115853.1628216-1-sakari.ailus@linux.in
> >>>>>>>>> tel.com/
> >>>>>>>>>
> >>>>>>>>> So imx-media-csi should be adjusted as well, no?
> >>>>>>>>
> >>>>>>>> It would really be helpful if you can give that series a spin on imx6
> >>>>>>>> if you already have a test setup.
> >>>>>>>
> >>>>>>> I tried, but it failed to apply on my current development tree. What base does
> >>>>>>> this series apply to? Is there also a repository available I can fetch from?
> >>>>>>
> >>>>>> Sakari could tell, for me it applied on v6.3-rc2 but I recall I had to
> >>>>>> manually fix a few things.
> >>>>>
> >>>>> Don't try v1, it won't work. I missed some object relation changes in the
> >>>>> linked lists. I'll post v2, hopefully some time next week, to address these
> >>>>> issues.
> >>>>
> >>>> Hi, Thorsten here, the Linux kernel's regression tracker.
> >>>>
> >>>> I see that v2[1] got a lot of ACKs, but is not even yet in next. And
> >>>> it's a lot of patches, so maybe too much for backporting to stable
> >>>> kernels. Which leads to the question: Will the regression this thread is
> >>>> about (introduced in 5.19 afaics) ever be fixed in v6.1?
> >>>> Normally/Ideally it should be.
> >>>
> >>> We'll need v3 (at least), a problem that's not trivial to fix was
> >>> identified with v2. There patches aren't really fixes either: it's new
> >>> functionality that wasn't there previously. I.MX6 just happened to work due
> >>> to missing checks in the V4L2 async framework, what it needs was never
> >>> supported (without this set).
> >>>
> >>> Dropping endpoint matching will break adv748x driver that relies on it.
> >>>
> >>> So I'd expect i.MX6 to work again once we have this set in, but I wouldn't
> >>> try to backport the set.
> >>
> >> Thx for the update. Makes me wonder if reverting the culprit[1] is an
> >> option. Assuming the problem still happens. Alexander, is that the case?
> >>
> >> Ciao, Thorsten
> >>
> >> [1] 1f391df4460 ("media: v4l2-async: Use endpoints in
> >> __v4l2_async_nf_add_fwnode_remote()") (v5.19-rc1; authored by Laurent,
> >> commited by Mauro (both now CCed))
> > 
> > I prioritise an in-kernel driver over a staging driver.
> 
> Sorry, can't follow. I track regressions all over the kernel and try to
> follow the best I can, but here I failed, as I have no idea which
> staging driver I mean.
> 
> I see a regression that is not really addressed and I wonder if there is
> a way to fix this until a proper solution is ready. Usually in this
> cases the culprit is reverted, unless that itself would cause another
> regression. Is that the case here? It sounds a bit like it, but would be
> great if somebody could confirm that.

As I explained earlier, reverting the patch will break adv748x.

-- 
Sakari Ailus

Re: v4l2-async: regression due to endpoint matching

[Linux regression tracking #adding (Thorsten Leemhuis)]

On 28.04.23 08:52, Linux regression tracking #adding (Thorsten Leemhuis)
wrote:
> [CCing the regression list, as it should be in the loop for regressions:
> https://docs.kernel.org/admin-guide/reporting-regressions.html]
> 
> [TLDR: I'm adding this report to the list of tracked Linux kernel
> regressions; the text you find below is based on a few templates
> paragraphs you might have encountered already in similar form.
> See link in footer if these mails annoy you.]
> 
> On 27.04.23 16:40, Alexander Stein wrote:
>>
>> I have a setup on my TQMa6x (imx6q-mba6a.dts) with a tc358743 attached to the 
>> MIPI CSI input.
>> I noticed that since commit 1f391df44607 ("media: v4l2-async: Use endpoints in 
>> __v4l2_async_nf_add_fwnode_remote()") the async subdevice probing does not 
>> work anymore. If I revert that, it is working again, even on next-20230425.
>> [...]
> 
> Thanks for the report. To be sure the issue doesn't fall through the
> cracks unnoticed, I'm adding it to regzbot, the Linux kernel regression
> tracking bot:
> 
> #regzbot ^introduced 1f391df44607
> #regzbot title media: v4l2-async: async subdevice probing stopped
> working on TQMa6x
> #regzbot ignore-activity

I'm removing this from the list of tracked regressions, because as I
understand things a revert would cause a regressions itself; a quick fix
sadly is not really possible and a proper one already WIP[1]. There
hence is not much worth tracking this. Should happen in a ideal world,
but that's how it is sometimes:

#regzbot inconclusive: revert no option and a proper fix will take some time
#regzbot ignore-activity

[1] afaics it's this, but I might be wrong with
https://lore.kernel.org/all/20230622114028.908825-1-sakari.ailus@linux.intel.com/

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
--
Everything you wanna know about Linux kernel regression tracking:
https://linux-regtracking.leemhuis.info/about/#tldr
That page also explains what to do if mails like this annoy you.