From: Michael Walle <michael@walle.cc>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
intel-wired-lan@lists.osuosl.org,
Bjorn Helgaas <bhelgaas@google.com>,
Jesse Brandeburg <jesse.brandeburg@intel.com>,
Tony Nguyen <anthony.l.nguyen@intel.com>,
Paul Menzel <pmenzel@molgen.mpg.de>
Subject: Re: [PATCH v2] PCI: Fix Intel i210 by avoiding overlapping of BARs
Date: Mon, 20 Dec 2021 18:43:03 +0100 [thread overview]
Message-ID: <9303c33a8faa83597db807a8c418ef17@walle.cc> (raw)
In-Reply-To: <5d41bad0e0607e68d9189667a45f7519@walle.cc>
Am 2021-08-20 17:12, schrieb Michael Walle:
> Am 2021-03-15 22:51, schrieb Michael Walle:
>> Am 2021-02-01 23:20, schrieb Bjorn Helgaas:
>>> On Mon, Feb 01, 2021 at 08:49:16PM +0100, Michael Walle wrote:
>>>> Am 2021-01-17 20:27, schrieb Michael Walle:
>>>> > Am 2021-01-16 00:57, schrieb Bjorn Helgaas:
>>>> > > On Wed, Jan 13, 2021 at 12:32:32AM +0100, Michael Walle wrote:
>>>> > > > Am 2021-01-12 23:58, schrieb Bjorn Helgaas:
>>>> > > > > On Sat, Jan 09, 2021 at 07:31:46PM +0100, Michael Walle wrote:
>>>> > > > > > Am 2021-01-08 22:20, schrieb Bjorn Helgaas:
>>>> > >
>>>> > > > > > > 3) If the Intel i210 is defective in how it handles an Expansion ROM
>>>> > > > > > > that overlaps another BAR, a quirk might be the right fix. But my
>>>> > > > > > > guess is the device is working correctly per spec and there's
>>>> > > > > > > something wrong in how firmware/Linux is assigning things. That would
>>>> > > > > > > mean we need a more generic fix that's not a quirk and not tied to the
>>>> > > > > > > Intel i210.
>>>> > > > > >
>>>> > > > > > Agreed, but as you already stated (and I've also found that in
>>>> > > > > > the PCI spec) the Expansion ROM address decoder can be shared by
>>>> > > > > > the other BARs and it shouldn't matter as long as the ExpROM BAR
>>>> > > > > > is disabled, which is the case here.
>>>> > > > >
>>>> > > > > My point is just that if this could theoretically affect devices
>>>> > > > > other than the i210, the fix should not be an i210-specific quirk.
>>>> > > > > I'll assume this is a general problem and wait for a generic PCI
>>>> > > > > core solution unless it's i210-specific.
>>>> > > >
>>>> > > > I guess the culprit here is that linux skips the programming of the
>>>> > > > BAR because of some broken Matrox card. That should have been a
>>>> > > > quirk instead, right? But I don't know if we want to change that, do
>>>> > > > we? How many other cards depend on that?
>>>> > >
>>>> > > Oh, right. There's definitely some complicated history there that
>>>> > > makes me a little scared to change things. But it's also unfortunate
>>>> > > if we have to pile quirks on top of quirks.
>>>> > >
>>>> > > > And still, how do we find out that the i210 is behaving correctly?
>>>> > > > In my opinion it is clearly not. You can change the ExpROM BAR value
>>>> > > > during runtime and it will start working (while keeping it
>>>> > > > disabled). Am I missing something here?
>>>> > >
>>>> > > I agree; if the ROM BAR is disabled, I don't think it should matter at
>>>> > > all what it contains, so this does look like an i210 defect.
>>>> > >
>>>> > > Would you mind trying the patch below? It should update the ROM BAR
>>>> > > value even when it is disabled. With the current pci_enable_rom()
>>>> > > code that doesn't rely on the value read from the BAR, I *think* this
>>>> > > should be safe even on the Matrox and similar devices.
>>>> >
>>>> > Your patch will fix my issue:
>>>> >
>>>> > Tested-by: Michael Walle <michael@walle.cc>
>>>>
>>>> any news on this?
>>>
>>> Thanks for the reminder. I was thinking this morning that I need to
>>> get back to this. I'm trying to convince myself that doing this
>>> wouldn't break the problem fixed by 755528c860b0 ("Ignore disabled
>>> ROM
>>> resources at setup"). So far I haven't quite succeeded.
>>
>> ping #2 ;)
>
> ping #3, soon we can celebrate our first one year anniversary :p
ping #4
In a few days this is a year old. Please have a look at it and either
add
my quirk patch or apply your patch. This is still breaking i210 on
my board.
TBH, this is really frustrating.
-michael
next prev parent reply other threads:[~2021-12-20 17:43 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-30 18:53 [PATCH v2] PCI: Fix Intel i210 by avoiding overlapping of BARs Michael Walle
2021-01-08 21:20 ` Bjorn Helgaas
2021-01-09 18:31 ` Michael Walle
2021-01-12 22:58 ` Bjorn Helgaas
2021-01-12 23:32 ` Michael Walle
2021-01-15 23:57 ` Bjorn Helgaas
2021-01-17 19:27 ` Michael Walle
2021-02-01 19:49 ` Michael Walle
2021-02-01 22:20 ` Bjorn Helgaas
2021-03-15 21:51 ` Michael Walle
2021-08-20 15:12 ` Michael Walle
2021-12-20 17:43 ` Michael Walle [this message]
2021-12-21 17:48 ` Bjorn Helgaas
2021-12-23 9:27 ` Michael Walle
2021-12-23 16:37 ` Bjorn Helgaas
2021-12-23 18:12 ` Michael Walle
2022-01-12 14:50 ` Bjorn Helgaas
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