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From: "Pali Rohár" <pali@kernel.org>
To: "Toke Høiland-Jørgensen" <toke@redhat.com>
Cc: vtolkm@gmail.com, "Bjorn Helgaas" <helgaas@kernel.org>,
	linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	"Rob Herring" <robh@kernel.org>,
	"Ilias Apalodimas" <ilias.apalodimas@linaro.org>,
	"Marek Behún" <marek.behun@nic.cz>,
	"Thomas Petazzoni" <thomas.petazzoni@bootlin.com>
Subject: Re: PCI trouble on mvebu (Turris Omnia)
Date: Wed, 31 Mar 2021 18:15:42 +0200	[thread overview]
Message-ID: <20210331161542.3e57qdtwnoz74xea@pali> (raw)
In-Reply-To: <87im57pgjh.fsf@toke.dk>

On Wednesday 31 March 2021 16:02:42 Toke Høiland-Jørgensen wrote:
> Pali Rohár <pali@kernel.org> writes:
> 
> > On Friday 26 March 2021 18:51:42 Toke Høiland-Jørgensen wrote:
> >> Pali Rohár <pali@kernel.org> writes:
> >> > On Friday 26 March 2021 17:54:38 Toke Høiland-Jørgensen wrote:
> >> >> So we have these
> >> >> cases:
> >> >> 
> >> >> ASPM disabled:          ath9k, ath10k and mt76 cards all work
> >> >> ASPM enabled, no patch: only mt76 card works
> >> >> ASPM enabled + patch:   ath10k and mt76 cards work
> >> >> 
> >> >> So IDK, maybe the ath9k card needs a quirk as well? Or the mvebu board
> >> >> is just generally flaky?
> >> >
> >> > I'm not sure. Maybe ASPM is somehow buggy on ath9k or needs some special
> >> > handling. But issue is not at PCI config space as ath9k driver start
> >> > initialization of this card. Needs also some debugging in ath9k driver
> >> > if it prints that strange "mac chip rev" error.
> >> 
> >> Well that's just being output because it gets a revision that it doesn't
> >> recognise - which it seems to be just reading from a register:
> >> 
> >> https://elixir.bootlin.com/linux/latest/source/drivers/net/wireless/ath/ath9k/hw.c#L255
> >> 
> >> The value returned is consistent with the value returned just being
> >> 0xffffffff. Which from looking at ioread32() is the value being returned
> >> on a failed read. So there's a driver bug there - the check against -EIO
> >> here is obviously nonsensical:
> >> 
> >> https://elixir.bootlin.com/linux/latest/source/drivers/net/wireless/ath/ath9k/hw.c#L290
> >> 
> >> But the underlying cause appears to be that the read from the register
> >> fails, which I suppose is related to something the PCI bus does?
> >> 
> >> > I think this issue should be handled separately. Could you report it
> >> > also to ath9k mailing list (and CC me)? Maybe other ath developers would
> >> > know some more details.
> >> 
> >> I'll send a patch for the nonsensical check above, but other than that I
> >> think we're still in PCI land here, or?
> >
> > First, can you try to enable my quirk also for this ath9k card with ASPM
> > enabled?
> 
> Yup, with this I get both devices working:
> 
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index 8ff690c7679d..7e2f9c69f6b2 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -3583,6 +3583,7 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ATHEROS, 0x0034, quirk_no_bus_reset);
>   * PCIe bridge has forced link speed to 2.5 GT/s via PCI_EXP_LNKCTL2 register.
>   */
>  DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ATHEROS, 0x003c, quirk_no_bus_reset_and_no_retrain_link);
> +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ATHEROS, 0x002e, quirk_no_bus_reset_and_no_retrain_link);
>  
>  /*
>   * Root port on some Cavium CN8xxx chips do not successfully complete a bus

Ok, thank you for testing!

I'm seeing that testing unit 0x0030 (AR93xx) also needs this quirk, so I
will mark all Atheros chips in above no bus reset list with no retrain
link quirk.

> >
> > I have there another ath9k card which after toggling link retraining
> > changes PCI device ID (really!) to 0xABCD. But lspci ...
> >
> > There is long story about broken ath9k cards that are reporting 0xABCD
> > id on x86 machines with specific BIOS versions. It can be find in
> > ath9k-devel mailing list archive:
> >
> > https://www.mail-archive.com/ath9k-devel@lists.ath9k.org/msg07529.html
> >
> > Maybe we now found root cause of this ABCD? If yes, then it also answers
> > why above ath9k driver check fails (device id was changed) and also
> > because kernel see correct id (kernel reads id before configuring ASPM
> > and therefore before triggering link retraining).
> >
> >> >> > Can you send PCI device id of your ath9k card (lspci -nn)? Because all
> >> >> > my tested ath9k cards have different PCI device id.
> >> >> 
> >> >> [root@omnia-arch ~]# lspci -nn
> >> >> 00:01.0 PCI bridge [0604]: Marvell Technology Group Ltd. Device [11ab:6820] (rev 04)
> >> >> 00:02.0 PCI bridge [0604]: Marvell Technology Group Ltd. Device [11ab:6820] (rev 04)
> >> >> 00:03.0 PCI bridge [0604]: Marvell Technology Group Ltd. Device [11ab:6820] (rev 04)
> >> >> 01:00.0 Network controller [0280]: Qualcomm Atheros AR9287 Wireless Network Adapter (PCI-Express) [168c:002e] (rev 01)
> >> >> 02:00.0 Network controller [0280]: Qualcomm Atheros QCA986x/988x 802.11ac Wireless Network Adapter [168c:003c]
> >> >
> >> > That is fine. Also all ath9k testing cards have id 0x002e.
> >
> > Today I found out that lspci -nn may lie! Please send output from
> > command: lspci -nn -x because real PCI device id can read only from -x
> > hexdump output.
> 
> Without the quirk added to the ath9k:
> 
> 01:00.0 Network controller [0280]: Qualcomm Atheros AR9287 Wireless Network Adapter (PCI-Express) [168c:002e] (rev 01)
> 00: 8c 16 2e 00 02 00 10 00 01 00 80 02 10 00 00 00
> 10: 04 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> 20: 00 00 00 00 00 00 00 00 00 00 00 00 8c 16 a4 30
> 30: 00 00 00 00 40 00 00 00 00 00 00 00 3d 01 00 00
> 
> 02:00.0 Network controller [0280]: Qualcomm Atheros QCA986x/988x 802.11ac Wireless Network Adapter [168c:003c]
> 00: 8c 16 3c 00 46 05 10 00 00 00 80 02 10 00 00 00
> 10: 04 00 20 e0 00 00 00 00 00 00 00 00 00 00 00 00
> 20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> 30: 00 00 20 ea 40 00 00 00 00 00 00 00 3e 01 00 00
> 
> And with:
> 
> 01:00.0 Network controller [0280]: Qualcomm Atheros AR9287 Wireless Network Adapter (PCI-Express) [168c:002e] (rev 01)
> 00: 8c 16 2e 00 46 01 10 00 01 00 80 02 10 00 00 00
> 10: 04 00 00 e0 00 00 00 00 00 00 00 00 00 00 00 00
> 20: 00 00 00 00 00 00 00 00 00 00 00 00 8c 16 a4 30
> 30: 00 00 00 00 40 00 00 00 00 00 00 00 3d 01 00 00
> 
> 02:00.0 Network controller [0280]: Qualcomm Atheros QCA986x/988x 802.11ac Wireless Network Adapter [168c:003c]
> 00: 8c 16 3c 00 46 05 10 00 00 00 80 02 10 00 00 00
> 10: 04 00 20 e0 00 00 00 00 00 00 00 00 00 00 00 00
> 20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> 30: 00 00 20 ea 40 00 00 00 00 00 00 00 3e 01 00 00
> 

Yesterday both MJ and Bjorn told me to use lspci '-b' switch which
instruct lspci to parse capabilities from config space (instead of
kernel cache).

Could you try to run 'lspci -nn -vv' and 'lspci -nn -vv -b' and compare
results? If something changes?

Anyway I have discussion with Adrian Chadd about 0xABCD issue and these
Qualcomm/Atheros cards. When post-AR9300 card is not initialized it
reports PCI device id 0xABCD. Pre-AR9300 cards should report correct PCI
device id even when it is not initialized. WLE200 is AR9287-based, so it
reports always correct id, should not change it during usage.

But seems that also this AR9287 has issue with EEPROM/OTP as you figured
out that ath9k driver is not able to read some device id from internal
register. So please prepare patch for fixing -EIO in ath9k.

PCI vendor & device id is in first 4 bytes and as you can see it is
correct and was not changed.

So I guess lspci output would not change for this card.

> Is that change in bytes 5 and 6 significant?

At offset 0x04 is 16bit PCI Command Register.

In second (with) output is set bit 2 which means that Bus Mastering is
enabled. This is normal and required when card communicate with system.
Then is enabled bit 6 (Parity Error Response) and bit 8 (SERR# Enable),
both for error reporting. This is normal when device is active.

So nothing suspicious here.

> -Toke
> 

  reply	other threads:[~2021-03-31 16:16 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-27 15:43 Toke Høiland-Jørgensen
2020-10-27 17:20 ` Bjorn Helgaas
2020-10-27 17:44   ` ™֟☻̭҇ Ѽ ҉ ®
2020-10-27 18:59     ` Toke Høiland-Jørgensen
2020-10-27 20:20       ` Toke Høiland-Jørgensen
2020-10-27 21:22         ` ™֟☻̭҇ Ѽ ҉ ®
2020-10-27 21:31           ` Toke Høiland-Jørgensen
2020-10-27 22:01             ` ™֟☻̭҇ Ѽ ҉ ®
2020-10-27 22:12               ` Toke Høiland-Jørgensen
2020-10-27 18:56   ` Toke Høiland-Jørgensen
2020-10-28 13:36     ` Toke Høiland-Jørgensen
2020-10-28 14:42       ` Bjorn Helgaas
2020-10-28 15:08         ` Toke Høiland-Jørgensen
2020-10-28 16:40           ` ™֟☻̭҇ Ѽ ҉ ®
2020-10-28 23:16             ` Bjorn Helgaas
2020-10-29 10:09               ` Pali Rohár
2020-10-29 10:56                 ` ™֟☻̭҇ Ѽ ҉ ®
2020-10-29 11:12                 ` Toke Høiland-Jørgensen
2020-10-29 19:30                   ` Bjorn Helgaas
2020-10-29 19:56                     ` ™֟☻̭҇ Ѽ ҉ ®
2020-10-29 19:57                     ` Andrew Lunn
2020-10-29 21:55                       ` Thomas Petazzoni
2020-10-29 20:18                     ` Toke Høiland-Jørgensen
2020-10-29 22:09                       ` Toke Høiland-Jørgensen
2020-10-29 20:58                     ` Marek Behun
2020-10-30 10:08                       ` Pali Rohár
2020-10-30 10:45                         ` Marek Behun
2020-10-29 21:54                     ` Thomas Petazzoni
2020-10-29 23:15                       ` Toke Høiland-Jørgensen
2020-10-30  8:23                         ` Thomas Petazzoni
2020-10-30 10:15                         ` Pali Rohár
2020-10-29 10:41               ` Toke Høiland-Jørgensen
2020-10-29 11:18                 ` ™֟☻̭҇ Ѽ ҉ ®
2020-10-30 11:23               ` Pali Rohár
2020-10-30 13:02                 ` Toke Høiland-Jørgensen
2020-10-30 14:23                   ` Pali Rohár
2020-10-30 14:54                     ` ™֟☻̭҇ Ѽ ҉ ®
2020-10-31 12:49                       ` Toke Høiland-Jørgensen
2020-11-02 15:24                         ` Pali Rohár
2020-11-02 15:54                           ` Toke Høiland-Jørgensen
2020-11-02 16:18                             ` ™֟☻̭҇ Ѽ ҉ ®
2020-11-02 16:33                               ` Toke Høiland-Jørgensen
2021-03-15 19:58                             ` Pali Rohár
2021-03-16  9:25                               ` Pali Rohár
2021-03-18 22:43                                 ` Toke Høiland-Jørgensen
2021-03-18 23:16                                   ` Pali Rohár
2021-03-26 12:50                                     ` Pali Rohár
2021-03-26 15:25                                       ` Toke Høiland-Jørgensen
2021-03-26 15:34                                         ` Pali Rohár
2021-03-26 16:54                                           ` Toke Høiland-Jørgensen
2021-03-26 17:11                                             ` Pali Rohár
2021-03-26 17:51                                               ` Toke Høiland-Jørgensen
2021-03-29 17:09                                                 ` Pali Rohár
2021-03-31 14:02                                                   ` Toke Høiland-Jørgensen
2021-03-31 16:15                                                     ` Pali Rohár [this message]
2021-03-31 16:53                                                       ` Toke Høiland-Jørgensen
2020-10-29  1:21             ` Marek Behun
2020-10-29 15:12           ` Rob Herring
2020-10-27 18:03 ` Marek Behun
2020-10-27 19:00   ` Toke Høiland-Jørgensen
2020-10-27 20:19     ` Marek Behun
2020-10-27 20:49       ` Toke Høiland-Jørgensen

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