Re: Aw: Re: Re: [PATCH 09/13] PCI: mediatek: Advertise lack of MSI handling

[Robin Murphy]

On 2021-03-01 14:06, Frank Wunderlich wrote:
> > Gesendet: Montag, 01. März 2021 um 14:31 Uhr
> > Von: "Marc Zyngier" <maz@xxxxxxxxxx>
> >
> > Frank,
> >
> > > > > i guess it's a bug in ath10k driver or my r64 board (it is a v1.1
> > > > > which has missing capacitors on tx lines).
> > > >
> > > > No, this definitely looks like a bug in the MTK PCIe driver,
> > > > where the mutex is either not properly initialised, corrupted,
> > > > or the wrong pointer is passed.
> > >
> > > but why does it happen only with the ath10k-card and not the mt7612 in
> > > same slot?
> >
> > Does mt7612 use MSI? What we have here is a bogus mutex in the
> > MTK PCIe driver, and the only way not to get there would be
> > to avoid using MSIs.
>
> i guess this card/its driver does not use MSI. Did not found anything in "datasheet" [1] or driver [2] about msi

FWIW, no need to guess - `lspci -v` (as root) should tell you whether 
the card has MSI (and/or MSI-X) capability, and whether it is enabled if so.

Robin.

> > > > This r64 machine is supposed to have working MSIs, right?
> > >
> > > imho mt7622 have working MSI
> > >
> > > > Do you get the same issue without this series?
> > >
> > > tested 5.11.0 [1] without this series (but with your/thomas' patch
> > > from discussion about my old patch) and got same trace. so this series
> > > does not break anything here.
> >
> > Can you retest without any additional patch on top of 5.11?
> > These two patches only affect platforms that do *not* have MSIs at all.
>
> i can revert these 2, but still need patches for mt7622 pcie-support [3]...btw. i see that i miss these in 5.11-main...do not see traceback with them (have firmware not installed...)
>
> root@bpi-r64:~# dmesg | grep ath
> [    6.450765] ath10k_pci 0000:01:00.0: assign IRQ: got 146
> [    6.661752] ath10k_pci 0000:01:00.0: enabling device (0000 -> 0002)
> [    6.697811] ath10k_pci 0000:01:00.0: enabling bus mastering
> [    6.721293] ath10k_pci 0000:01:00.0: pci irq msi oper_irq_mode 2 irq_mode 0 r
> eset_mode 0
> [    6.921030] ath10k_pci 0000:01:00.0: Failed to find firmware-N.bin (N between
>   2 and 6) from ath10k/QCA988X/hw2.0: -2
> [    6.931698] ath10k_pci 0000:01:00.0: could not fetch firmware files (-2)
> [    6.940417] ath10k_pci 0000:01:00.0: could not probe fw (-2)
>
> so traceback was caused by missing changes in mtk pcie-driver not yet upstream, added Chuanjia Liu
>
> > > > > Tried with an mt7612e, this seems to work without any errors.
> > > > >
> > > > > so for mt7622/mt7623
> > > > >
> > > > > Tested-by: Frank Wunderlich <frank-w@xxxxxxxxxxxxxxx>
> > > >
> > > > We definitely need to understand the above.
> > >
> > > there is a hardware-bug which may cause this...afair i saw this with
> > > the card in r64 with earlier Kernel-versions where other cards work
> > > (like the mt7612e).
> >
> > I don't think a HW bug affecting PCI would cause what we are seeing
> > here, unless it results in memory corruption.
>
>
> [1] https://www.asiarf.com/shop/wifi-wlan/wifi_mini_pcie/ws2433-wifi-11ac-mini-pcie-module-manufacturer/
> [2] grep -Rni 'msi' drivers/net/wireless/mediatek/mt76/mt76x2/
> [3] https://patchwork.kernel.org/project/linux-mediatek/list/?series=372885
>
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