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From: "Raj, Ashok" <ashok.raj@intel.com>
To: Sinan Kaya <okaya@kernel.org>
Cc: "Stanislav Spassov" <stanspas@amazon.com>,
	linux-pci@vger.kernel.org,
	"Stanislav Spassov" <stanspas@amazon.de>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Jan H . Schönherr" <jschoenh@amazon.de>,
	"Jonathan Corbet" <corbet@lwn.net>,
	"Alex Williamson" <alex.williamson@redhat.com>,
	"Rajat Jain" <rajatja@google.com>,
	"Ashok Raj" <ashok.raj@intel.com>
Subject: Re: [PATCH v4 3/3] PCI: Add CRS handling to pci_dev_wait()
Date: Mon, 9 Mar 2020 09:19:51 -0700	[thread overview]
Message-ID: <20200309161951.GA25817@otc-nc-03> (raw)
In-Reply-To: <0461c706-579b-8c03-cf33-66e79890af92@kernel.org>

On Mon, Mar 09, 2020 at 11:55:11AM -0400, Sinan Kaya wrote:
> On 3/7/2020 12:20 PM, Stanislav Spassov wrote:
> > +		rc = pci_dev_poll_until_not_equal(dev, PCI_VENDOR_ID, 0xffff,
> > +						  0x0001, reset_type, timeout,
> > +						  &waited, &id);
> > +		if (rc)
> > +			return rc;
> > +
> 
> If I remember right, this doesn't work for VF sending CRS because VF
> always returns 0xffff for VENDOR_ID register.

Is this required by the PCIe spec? i think the only requirement is 
the 1s wait after PF has done the VF enable. See Implementation Note
right above section 2.3.1.1 in the Base spec 5.0. 

If this behavior is different for maybe a specific SRIOV device we should
probably quirk the standard behavior?

The rules are mentioned in so many places, but looking through the 
SRIOV section's doesn't seem to specify special rules for VF's other than
the wait time after VF enable.



  reply	other threads:[~2020-03-09 16:19 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-07 17:20 [PATCH v4 0/3] Improve PCI device post-reset readiness polling Stanislav Spassov
2020-03-07 17:20 ` [PATCH v4 1/3] PCI: Refactor polling loop out of pci_dev_wait Stanislav Spassov
2020-03-07 17:20 ` [PATCH v4 2/3] PCI: Cache CRS Software Visibiliy in struct pci_dev Stanislav Spassov
2021-09-12 13:32   ` Bjorn Helgaas
2021-09-13 16:06     ` Spassov, Stanislav
2020-03-07 17:20 ` [PATCH v4 3/3] PCI: Add CRS handling to pci_dev_wait() Stanislav Spassov
2020-03-09 15:55   ` Sinan Kaya
2020-03-09 16:19     ` Raj, Ashok [this message]
2020-03-09 16:38       ` Spassov, Stanislav
2020-03-09 17:33         ` Sinan Kaya
2021-09-11 14:03   ` Bjorn Helgaas
2021-09-13 16:29     ` Spassov, Stanislav
2021-09-13 16:38       ` Bjorn Helgaas
2021-09-13 18:04         ` Spassov, Stanislav
2021-09-14 17:53           ` Rajat Jain
2021-09-13 16:07   ` Bjorn Helgaas
2021-09-13 16:39     ` Spassov, Stanislav
2021-01-22  8:54 ` [PATCH v4 0/3] Improve PCI device post-reset readiness polling David Woodhouse
2021-09-10  9:32   ` David Woodhouse

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