From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Walle Date: Mon, 01 Feb 2021 20:49:16 +0100 Subject: [Intel-wired-lan] [PATCH v2] PCI: Fix Intel i210 by avoiding overlapping of BARs In-Reply-To: <2477c66eafbd97207693b83b60fa0a3c@walle.cc> References: <20210115235721.GA1862880@bjorn-Precision-5520> <2477c66eafbd97207693b83b60fa0a3c@walle.cc> Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: intel-wired-lan@osuosl.org List-ID: Hi Bjorn, 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 any news on this? -michael