NACK: [F/Unstable/OEM-5.6] [PATCH 2/2] PCI: Avoid Pericom USB controller OHCI/EHCI PME# defect

[Stefan Bader]

On 18.05.20 15:16, Kai-Heng Feng wrote:
> BugLink: https://bugs.launchpad.net/bugs/1879321
> 
> Both Pericom OHCI and EHCI devices advertise PME# support from all power
> states:
> 
>   06:00.0 USB controller [0c03]: Pericom Semiconductor PI7C9X442SL USB OHCI Controller [12d8:400e] (rev 01) (prog-if 10 [OHCI])
>     Subsystem: Pericom Semiconductor PI7C9X442SL USB OHCI Controller [12d8:400e]
>     Capabilities: [80] Power Management version 3
>       Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=375mA PME(D0+,D1+,D2+,D3hot+,D3cold+)
> 
>   06:00.2 USB controller [0c03]: Pericom Semiconductor PI7C9X442SL USB EHCI Controller [12d8:400f] (rev 01) (prog-if 20 [EHCI])
>     Subsystem: Pericom Semiconductor PI7C9X442SL USB EHCI Controller [12d8:400f]
>     Capabilities: [80] Power Management version 3
>       Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=375mA PME(D0+,D1+,D2+,D3hot+,D3cold+)
> 
> But testing shows that it's unreliable: there is a 20% chance PME# won't be
> asserted when a USB device is plugged.
> 
> Remove PME support for both devices to make USB plugging work reliably.
> 
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=205981
> Link: https://lore.kernel.org/r/20200508065343.32751-2-kai.heng.feng@canonical.com
> Signed-off-by: Kai-Heng Feng <kai.heng.feng at canonical.com>
> Signed-off-by: Bjorn Helgaas <bhelgaas at google.com>
> Cc: stable at vger.kernel.org
> (backported from commit 68f5fc4ea9ddf9f77720d568144219c4e6452cde linux-next)
> Signed-off-by: Kai-Heng Feng <kai.heng.feng at canonical.com>
> ---

The original patch just adds a new fixup function and declarations. Your
backport removes apex_pci_fixup_class() without a real explanation why.

-Stefan

>  drivers/pci/quirks.c | 14 ++++++++++----
>  1 file changed, 10 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index 8ee5e15445cc..423a6e76314c 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -5606,9 +5606,15 @@ static void pci_fixup_no_d0_pme(struct pci_dev *dev)
>  }
>  DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ASMEDIA, 0x2142, pci_fixup_no_d0_pme);
>  
> -static void apex_pci_fixup_class(struct pci_dev *pdev)
> +/*
> + * Device [12d8:0x400e] and [12d8:0x400f]
> + * These devices advertise PME# support in all power states but don't
> + * reliably assert it.
> + */
> +static void pci_fixup_no_pme(struct pci_dev *dev)
>  {
> -	pdev->class = (PCI_CLASS_SYSTEM_OTHER << 8) | pdev->class;
> +	pci_info(dev, "PME# is unreliable, disabling it\n");
> +	dev->pme_support = 0;
>  }
> -DECLARE_PCI_FIXUP_CLASS_HEADER(0x1ac1, 0x089a,
> -			       PCI_CLASS_NOT_DEFINED, 8, apex_pci_fixup_class);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_PERICOM, 0x400e, pci_fixup_no_pme);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_PERICOM, 0x400f, pci_fixup_no_pme);
> 


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