Gentle ping...
> Subject: RE: [PATCH] mailbox: imx: Add context save/restore for > suspend/resume > > > > > Subject: RE: [PATCH] mailbox: imx: Add context save/restore for > > suspend/resume > > > > > From: Anson Huang <[email protected]> > > > Sent: Friday, April 24, 2020 10:33 AM > > > > > > > Subject: RE: [PATCH] mailbox: imx: Add context save/restore for > > > > suspend/resume > > > > > > > > > From: Anson Huang <[email protected]> > > > > > Sent: Friday, April 24, 2020 7:01 AM > > > > > > > > > > For "mem" mode suspend on i.MX8 SoCs, MU settings could be lost > > > > > because its power is off, so save/restore is needed for MU > > > > > settings during > > > > suspend/resume. > > > > > However, the restore can ONLY be done when MU settings are > > > > > actually lost, for the scenario of settings NOT lost in "freeze" > > > > > mode suspend, since there could be still IPC going on multiple > > > > > CPUs, restoring the MU settings could overwrite the TIE by > > > > > mistake and cause system freeze, so need to make sure ONLY > > > > > restore the MU settings when it is > > > > powered off. > > > > > > > > > > Signed-off-by: Anson Huang <[email protected]> > > > > > > > > As mentioned before, we'd better keep the original author. > > > > > > > > > --- > > > > > drivers/mailbox/imx-mailbox.c | 35 > > > > > +++++++++++++++++++++++++++++++++++ > > > > > 1 file changed, 35 insertions(+) > > > > > > > > > > diff --git a/drivers/mailbox/imx-mailbox.c > > > > > b/drivers/mailbox/imx-mailbox.c index 97bf0ac..b53cf63 100644 > > > > > --- a/drivers/mailbox/imx-mailbox.c > > > > > +++ b/drivers/mailbox/imx-mailbox.c > > > > > @@ -67,6 +67,8 @@ struct imx_mu_priv { > > > > > struct clk *clk; > > > > > int irq; > > > > > > > > > > + u32 xcr; > > > > > + > > > > > bool side_b; > > > > > }; > > > > > > > > > > @@ -583,12 +585,45 @@ static const struct of_device_id > > > > > imx_mu_dt_ids[] = { }; MODULE_DEVICE_TABLE(of, imx_mu_dt_ids); > > > > > > > > > > +static int imx_mu_suspend_noirq(struct device *dev) { > > > > > + struct imx_mu_priv *priv = dev_get_drvdata(dev); > > > > > + > > > > > + priv->xcr = imx_mu_read(priv, priv->dcfg->xCR); > > > > > + > > > > > + return 0; > > > > > +} > > > > > + > > > > > +static int imx_mu_resume_noirq(struct device *dev) { > > > > > + struct imx_mu_priv *priv = dev_get_drvdata(dev); > > > > > + > > > > > + /* > > > > > + * ONLY restore MU when context lost, the TIE could > > > > > + * be set during noirq resume as there is MU data > > > > > + * communication going on, and restore the saved > > > > > + * value will overwrite the TIE and cause MU data > > > > > + * send failed, may lead to system freeze. This issue > > > > > + * is observed by testing freeze mode suspend. > > > > > + */ > > > > > + if (!imx_mu_read(priv, priv->dcfg->xCR)) > > > > > + imx_mu_write(priv, priv->xcr, priv->dcfg->xCR); > > > > > > > > This could be separate patch if it aims to fix a specific corner case. > > > > > > This is NOT corner case, it can be reproduced with our imx_5.4.y > > > very easily, and this issue cause me many days to debug...Also cause > > > Clark's effort to help test it a lot for many days... > > > > > > > Is this issue only happen for non-state lost case (eg. Freeze mode)? > > If yes, it's a specific case and worth a separate patch to highlight it > > IMHO. > > > > BTW, it seems most drivers have this issue in current kernel because > > they don't know whether the state are really lost, it seems like > > kernel still doesn't support this well. > > > > > I do NOT think it makes sense to first send out your patch with bug > > > for review, And then add another patch to fix it. 1 patch is enough > > > for this > > feature. > > > > > > > Anyway, if you really want to go with one patch, for this case, we > > usually could keep original author and add a small fix note in commit > message. > > (You could see many community guys do like this if you search kernel > > commit > > log) > > > > Basically we try our best to keep origin author in order to respect > > others' work for community work. > > I am fine with whoever is the author, my focus is the issue fix and easy > rebase. > If maintainer agrees that introduce a patch with bug and add another patch to > fix is OK, then I can rework the patch into 2 patches. > > Anson
