regressions.lists.linux.dev archive mirror
 help / color / mirror / Atom feed
From: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
To: Carl Huang <cjhuang@codeaurora.org>
Cc: Kalle Valo <kvalo@codeaurora.org>,
	Loic Poulain <loic.poulain@linaro.org>,
	ath11k@lists.infradead.org,
	linux-arm-msm <linux-arm-msm@vger.kernel.org>,
	linux-wireless@vger.kernel.org, regressions@lists.linux.dev
Subject: Re: [regression] mhi: ath11k resume fails on some devices
Date: Thu, 23 Sep 2021 14:29:26 +0530	[thread overview]
Message-ID: <20210923085926.GD6083@thinkpad> (raw)
In-Reply-To: <b7c0906041dcafb43be215bd4f55326a@codeaurora.org>

On Thu, Sep 23, 2021 at 04:34:43PM +0800, Carl Huang wrote:
> On 2021-09-17 01:19, Manivannan Sadhasivam wrote:
> > On Thu, Sep 16, 2021 at 07:42:02PM +0300, Kalle Valo wrote:
> > > Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> writes:
> > > 
> > > > On Thu, Sep 16, 2021 at 01:18:22PM +0200, Loic Poulain wrote:
> > > >> Le jeu. 16 sept. 2021 à 13:12, Manivannan Sadhasivam <
> > > >> manivannan.sadhasivam@linaro.org> a écrit :
> > > >>
> > > >
> > > > [...]
> > > >
> > > >> > If things seems to work fine without that patch, then it implies that
> > > >> > setting M0
> > > >> > state works during resume. I think we should just revert that patch.
> > > >> >
> > > >> > Loic, did that patch fix any issue for you or it was a cosmetic fix only?
> > > >>
> > > >>
> > > >> It fixes sdx modem resuming issue, without that we don’t know modem needs
> > > >> to be reinitialized.
> > > >>
> > > >
> > > > Okay. Then in that case, the recovery mechanism has to be added to the ath11k
> > > > MHI controller.
> > > 
> > > What does that mean in practise, do you have any pointers or
> > > examples? I
> > > have no clue what you are proposing :)
> > > 
> > 
> > Take a look at the mhi_pci_recovery_work() function below:
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/bus/mhi/pci_generic.c#n610
> > 
> > You need to implement something similar that basically powers up the MHI
> > endpoint (QCA6390) in case pm_resume() fails. At minimum, you need to
> > call
> > below functions:
> > 
> > # Check if the device is powered on. If yes, then power it down to bring
> > it back
> > mhi_power_down()
> > mhi_unprepare_after_power_down()
> > 
> > # Power up the device
> > mhi_prepare_for_power_up()
> > mhi_sync_power_up()
> > 
> > This implies that the WLAN device has been powered off during suspend,
> > so the
> > resume fails and we are bringing the device back to working state.
> > 
> This is fine for platform which doesn't provide power supply during suspend.
> But NUC has power supply in suspend state.

If NUC retains power supply during suspend then it should work with that commit.
During resume, the device is expected to be in M3 state and that's what the
commit verifies.

If the device is in a different state, then most likely the device have power
cycled.

> QCA6390 on NUC works after just reverting this commit also proves NUC has
> power supply in
> suspend state.
> 

That's because we allowed the device to be in any state during resume and if it
responds to the M0 transition it worked.

> The reason is MHI-STATUS register can't be read somehow in M3 state on NUC.

No, that's not correct.

> Does the MHI spec state that MHI-STATUS register can be read in M3 state?
> 

Yes, all the MHI registers are accessible in all states. During M3, both MHI
host and device (if supported) will transition to D3 Cold. Then during resume,
host will switch to D0 link state and will also notify the device to enter D0.

For aid debugging, please see the state the device is in during mhi_pm_resume().
You can use below diff:

diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
index fb99e3727155..482d55dd209e 100644
--- a/drivers/bus/mhi/core/pm.c
+++ b/drivers/bus/mhi/core/pm.c
@@ -898,6 +898,9 @@ int mhi_pm_resume(struct mhi_controller *mhi_cntrl)
        if (MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state))
                return -EIO;
 
+       dev_info(dev, "Device state: %s\n",
+                TO_MHI_STATE_STR(mhi_get_mhi_state(mhi_cntrl)));
+
        if (mhi_get_mhi_state(mhi_cntrl) != MHI_STATE_M3)
                return -EINVAL;


Thanks,
Mani

  reply	other threads:[~2021-09-23  8:59 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-16  8:00 Kalle Valo
2021-09-16 10:18 ` Loic Poulain
2021-09-16 11:12   ` Manivannan Sadhasivam
     [not found]     ` <CAMZdPi94607mZorp+Zmkw3seWXak6p9Jr05CQ5hhfgKQoG8n7Q@mail.gmail.com>
2021-09-16 16:35       ` Manivannan Sadhasivam
2021-09-16 16:42         ` Kalle Valo
2021-09-16 17:19           ` Manivannan Sadhasivam
2021-09-23  8:34             ` Carl Huang
2021-09-23  8:59               ` Manivannan Sadhasivam [this message]
2021-09-23  9:26                 ` Carl Huang
2021-09-23 10:50                   ` Loic Poulain
2021-09-24  9:07                 ` Kalle Valo
2021-09-24  9:57                   ` Manivannan Sadhasivam
2021-10-07  9:55                     ` Kalle Valo
2021-10-21 10:01                       ` Manivannan Sadhasivam
2021-09-24  8:36   ` Kalle Valo
2021-09-24  9:43     ` Loic Poulain
2021-09-24 10:00       ` Manivannan Sadhasivam
2021-10-07  9:48       ` Kalle Valo
2021-10-19 12:12         ` Kalle Valo
2021-10-21 10:03           ` Manivannan Sadhasivam
2021-11-12 11:36             ` Thorsten Leemhuis
2021-11-18 17:41             ` Manivannan Sadhasivam
2021-12-01  7:34               ` Thorsten Leemhuis
2021-09-25 17:40 ` Thorsten Leemhuis

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210923085926.GD6083@thinkpad \
    --to=manivannan.sadhasivam@linaro.org \
    --cc=ath11k@lists.infradead.org \
    --cc=cjhuang@codeaurora.org \
    --cc=kvalo@codeaurora.org \
    --cc=linux-arm-msm@vger.kernel.org \
    --cc=linux-wireless@vger.kernel.org \
    --cc=loic.poulain@linaro.org \
    --cc=regressions@lists.linux.dev \
    --subject='Re: [regression] mhi: ath11k resume fails on some devices' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).