2020-09-29 19:09:19

by Rob Herring (Arm)

[permalink] [raw]
Subject: Re: [PATCH] ath10k: Introduce a devicetree quirk to skip host cap QMI requests

On Fri, Sep 25, 2020 at 11:59:41PM +0530, Amit Pundir wrote:
> There are firmware versions which do not support host capability
> QMI request. We suspect either the host cap is not implemented or
> there may be firmware specific issues, but apparently there seem
> to be a generation of firmware that has this particular behavior.
>
> For example, firmware build on Xiaomi Poco F1 (sdm845) phone:
> "QC_IMAGE_VERSION_STRING=WLAN.HL.2.0.c3-00257-QCAHLSWMTPLZ-1"
>
> If we do not skip the host cap QMI request on Poco F1, then we
> get a QMI_ERR_MALFORMED_MSG_V01 error message in the
> ath10k_qmi_host_cap_send_sync(). But this error message is not
> fatal to the firmware nor to the ath10k driver and we can still
> bring up the WiFi services successfully if we just ignore it.
>
> Hence introducing this DeviceTree quirk to skip host capability
> QMI request for the firmware versions which do not support this
> feature.

So if you change the WiFi firmware, you may force a DT change too. Those
are pretty independent things otherwise.

Why can't you just always ignore this error? If you can't deal with this
entirely in the driver, then it should be part of the WiFi firmware so
it's always in sync.

Rob


2020-10-29 13:41:26

by Bjorn Andersson

[permalink] [raw]
Subject: Re: [PATCH] ath10k: Introduce a devicetree quirk to skip host cap QMI requests

On Tue 29 Sep 14:08 CDT 2020, Rob Herring wrote:

> On Fri, Sep 25, 2020 at 11:59:41PM +0530, Amit Pundir wrote:
> > There are firmware versions which do not support host capability
> > QMI request. We suspect either the host cap is not implemented or
> > there may be firmware specific issues, but apparently there seem
> > to be a generation of firmware that has this particular behavior.
> >
> > For example, firmware build on Xiaomi Poco F1 (sdm845) phone:
> > "QC_IMAGE_VERSION_STRING=WLAN.HL.2.0.c3-00257-QCAHLSWMTPLZ-1"
> >
> > If we do not skip the host cap QMI request on Poco F1, then we
> > get a QMI_ERR_MALFORMED_MSG_V01 error message in the
> > ath10k_qmi_host_cap_send_sync(). But this error message is not
> > fatal to the firmware nor to the ath10k driver and we can still
> > bring up the WiFi services successfully if we just ignore it.
> >
> > Hence introducing this DeviceTree quirk to skip host capability
> > QMI request for the firmware versions which do not support this
> > feature.
>
> So if you change the WiFi firmware, you may force a DT change too. Those
> are pretty independent things otherwise.
>

Yes and that's not good. But I looked at somehow derive this from
firmware version numbers etc and it's not working out, so I'm out of
ideas for alternatives.

> Why can't you just always ignore this error? If you can't deal with this
> entirely in the driver, then it should be part of the WiFi firmware so
> it's always in sync.
>

Unfortunately the firmware versions I've hit this problem on has gone
belly up when receiving this request, that's why I asked Amit to add a
flag to skip it.

That said, in the devices I've hit this I've managed to get newer
firmware working, which doesn't have either problem.

Regards,
Bjorn

2020-11-03 07:49:34

by Amit Pundir

[permalink] [raw]
Subject: Re: [PATCH] ath10k: Introduce a devicetree quirk to skip host cap QMI requests

Hi Rob, Bjorn, Kalle,

On Thu, 29 Oct 2020 at 19:10, Bjorn Andersson
<[email protected]> wrote:
>
> On Tue 29 Sep 14:08 CDT 2020, Rob Herring wrote:
>
> > On Fri, Sep 25, 2020 at 11:59:41PM +0530, Amit Pundir wrote:
> > > There are firmware versions which do not support host capability
> > > QMI request. We suspect either the host cap is not implemented or
> > > there may be firmware specific issues, but apparently there seem
> > > to be a generation of firmware that has this particular behavior.
> > >
> > > For example, firmware build on Xiaomi Poco F1 (sdm845) phone:
> > > "QC_IMAGE_VERSION_STRING=WLAN.HL.2.0.c3-00257-QCAHLSWMTPLZ-1"
> > >
> > > If we do not skip the host cap QMI request on Poco F1, then we
> > > get a QMI_ERR_MALFORMED_MSG_V01 error message in the
> > > ath10k_qmi_host_cap_send_sync(). But this error message is not
> > > fatal to the firmware nor to the ath10k driver and we can still
> > > bring up the WiFi services successfully if we just ignore it.
> > >
> > > Hence introducing this DeviceTree quirk to skip host capability
> > > QMI request for the firmware versions which do not support this
> > > feature.
> >
> > So if you change the WiFi firmware, you may force a DT change too. Those
> > are pretty independent things otherwise.
> >
>
> Yes and that's not good. But I looked at somehow derive this from
> firmware version numbers etc and it's not working out, so I'm out of
> ideas for alternatives.
>
> > Why can't you just always ignore this error? If you can't deal with this
> > entirely in the driver, then it should be part of the WiFi firmware so
> > it's always in sync.
> >
>
> Unfortunately the firmware versions I've hit this problem on has gone
> belly up when receiving this request, that's why I asked Amit to add a
> flag to skip it.

So what is next for this DT quirk?

I'm OK to go back to my previous of_machine_is_compatible()
device specific hack, for now,
https://patchwork.kernel.org/project/linux-wireless/patch/[email protected]/
till we have a reasonable fix in place or receive a vendor firmware
drop which fixes this problem (which I believe is highly unlikely
though, for this 2+ years old device).

Regards,
Amit Pundir

>
> That said, in the devices I've hit this I've managed to get newer
> firmware working, which doesn't have either problem.
>
> Regards,
> Bjorn

2020-11-24 17:56:24

by Bjorn Andersson

[permalink] [raw]
Subject: Re: [PATCH] ath10k: Introduce a devicetree quirk to skip host cap QMI requests

On Tue 03 Nov 01:48 CST 2020, Amit Pundir wrote:

> Hi Rob, Bjorn, Kalle,
>
> On Thu, 29 Oct 2020 at 19:10, Bjorn Andersson
> <[email protected]> wrote:
> >
> > On Tue 29 Sep 14:08 CDT 2020, Rob Herring wrote:
> >
> > > On Fri, Sep 25, 2020 at 11:59:41PM +0530, Amit Pundir wrote:
> > > > There are firmware versions which do not support host capability
> > > > QMI request. We suspect either the host cap is not implemented or
> > > > there may be firmware specific issues, but apparently there seem
> > > > to be a generation of firmware that has this particular behavior.
> > > >
> > > > For example, firmware build on Xiaomi Poco F1 (sdm845) phone:
> > > > "QC_IMAGE_VERSION_STRING=WLAN.HL.2.0.c3-00257-QCAHLSWMTPLZ-1"
> > > >
> > > > If we do not skip the host cap QMI request on Poco F1, then we
> > > > get a QMI_ERR_MALFORMED_MSG_V01 error message in the
> > > > ath10k_qmi_host_cap_send_sync(). But this error message is not
> > > > fatal to the firmware nor to the ath10k driver and we can still
> > > > bring up the WiFi services successfully if we just ignore it.
> > > >
> > > > Hence introducing this DeviceTree quirk to skip host capability
> > > > QMI request for the firmware versions which do not support this
> > > > feature.
> > >
> > > So if you change the WiFi firmware, you may force a DT change too. Those
> > > are pretty independent things otherwise.
> > >
> >
> > Yes and that's not good. But I looked at somehow derive this from
> > firmware version numbers etc and it's not working out, so I'm out of
> > ideas for alternatives.
> >
> > > Why can't you just always ignore this error? If you can't deal with this
> > > entirely in the driver, then it should be part of the WiFi firmware so
> > > it's always in sync.
> > >
> >
> > Unfortunately the firmware versions I've hit this problem on has gone
> > belly up when receiving this request, that's why I asked Amit to add a
> > flag to skip it.
>
> So what is next for this DT quirk?
>

Rob, we still have this problem and we've not come up with any way to
determine in runtime that we need to skip this part of the
initialization.

Regards,
Bjorn

> I'm OK to go back to my previous of_machine_is_compatible()
> device specific hack, for now,
> https://patchwork.kernel.org/project/linux-wireless/patch/[email protected]/
> till we have a reasonable fix in place or receive a vendor firmware
> drop which fixes this problem (which I believe is highly unlikely
> though, for this 2+ years old device).
>
> Regards,
> Amit Pundir
>
> >
> > That said, in the devices I've hit this I've managed to get newer
> > firmware working, which doesn't have either problem.
> >
> > Regards,
> > Bjorn