On Tue, Jan 14, 2025 at 02:26:22PM -0600, Bjorn Helgaas wrote:
> On Tue, Jan 14, 2025 at 02:32:38PM -0500, Frank Li wrote:
> > On Tue, Jan 14, 2025 at 12:15:18PM -0600, Bjorn Helgaas wrote:
> > > On Tue, Dec 10, 2024 at 04:15:56PM +0800, Richard Zhu wrote:
> > > > On i.MX8QM, PCIe link can't be re-established again in
> > > > dw_pcie_resume_noirq(), if the LTSSM_EN bit is not cleared properly in
> > > > dw_pcie_suspend_noirq().
> > > >
> > > > Add dw_pcie_stop_link() into dw_pcie_suspend_noirq() to fix this issue and
> > > > keep symmetric in suspend/resume function since there is
> > > > dw_pcie_start_link() in dw_pcie_resume_noirq().
> > > >
> > > > Fixes: 4774faf854f5 ("PCI: dwc: Implement generic suspend/resume functionality")
> > > > Signed-off-by: Richard Zhu <hongxing.zhu@xxxxxxx>
> > > > Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
> > > > ---
> > > > drivers/pci/controller/dwc/pcie-designware-host.c | 1 +
> > > > 1 file changed, 1 insertion(+)
> > > >
> > > > diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> > > > index f882b11fd7b94..f56cb7b9e6f99 100644
> > > > --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> > > > +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> > > > @@ -1001,6 +1001,7 @@ int dw_pcie_suspend_noirq(struct dw_pcie *pci)
> > > > return ret;
> > > > }
> > > >
> > > > + dw_pcie_stop_link(pci);
> > >
> > > We should try to avoid changes to the generic DWC path just to
> > > accommodate one controller. Since other DWC-based controllers
> > > apparently don't need dw_pcie_stop_link() here, this seems like it
> > > might be the wrong place for this change.
> > >
> > > If doing dw_pcie_stop_link() here is really helpful for all DWC
> > > controllers, this would be fine, but the commit log should then explain
> > > why it helps everybody, not why one particular controller benefits.
> >
> > It should be for all dwc controllers although find such problem at i.MX8QM
> > platfrom. It should keep symmetric between suspend/resume function.
> >
> > So far only layerscape and i.MX platform use these common functions. Other
> > dwc platform still have not switched to this common function yet.
>
> I see that layerscape uses dw_pcie_suspend_noirq():
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/pci/controller/dwc/pci-layerscape.c?id=v6.13-rc7#n379
>
> But I don't see where imx6 does:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/pci/controller/dwc/pci-imx6.c?id=v6.13-rc7#n1236
>
> We don't currently have anything queued that touches pci-imx6.c; am I
> missing a patch that converts pci-imx6.c to use
> dw_pcie_suspend_noirq()?
Oh! It is here,
https://lore.kernel.org/imx/20241126075702.4099164-9-hongxing.zhu@xxxxxxx/
I am not sure why still not merged yet. (Nov 26).
Can you help check "elimiated pci_fixup_addr() callback patches". I already
ping serial times. no one reply me. I think it is more important, so other
person can start clean up cpu_fixup_addr().
https://lore.kernel.org/imx/Z1i9uEGvsVACsF2r@lizhi-Precision-Tower-5810/
Frank
>
> This doesn't feel urgent yet since the commit log talks about i.MX8QM,
> but I can't make a connection between i.MX8QM and this patch.
>
> Bjorn
