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To:     Dave Jones <davej@codemonkey.org.uk>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Bjorn Helgaas <bhelgaas@google.com>
References: <CAHk-=wgbygOb3hRV+7YOpVcMPTP2oQ=iw6tf09Ydspg7o7BsWQ@mail.gmail.com>
 <20210913141818.GA27911@codemonkey.org.uk>
From:   Heiner Kallweit <hkallweit1@gmail.com>
Cc:     "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>
Subject: Re: Linux 5.15-rc1
Message-ID: <ab571d7e-0cf5-ffb3-6bbe-478a4ed749dc@gmail.com>
Date:   Mon, 13 Sep 2021 20:59:49 +0200
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On 13.09.2021 16:18, Dave Jones wrote:
> [  186.595296] pci 0000:02:00.0: [144d:a800] type 00 class 0x010601
> [  186.595351] pci 0000:02:00.0: reg 0x24: [mem 0xdfc10000-0xdfc11fff]
> [  186.595361] pci 0000:02:00.0: reg 0x30: [mem 0xdfc00000-0xdfc0ffff pref]
> [  186.595425] pci 0000:02:00.0: PME# supported from D3hot D3cold
> [  186.735107] pci 0000:02:00.0: VPD access failed.  This is likely a firmware bug on this device.  Contact the card vendor for a firmware update

Thanks for the report! The stalls may be related to this one. Device is:
02:00.0 SATA controller: Samsung Electronics Co Ltd XP941 PCIe SSD (rev 01)

With an older kernel you may experience the stall when accessing the vpd
attribute of this device in sysfs.

Maybe the device indicates VPD capability but doesn't actually support it.
Could you please provide the "lspci -vv" output for this device?

And could you please test with the following applied to verify the
assumption? It disables VPD access for this device.

---
 drivers/pci/vpd.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/pci/vpd.c b/drivers/pci/vpd.c
index 517789205..fc92e880e 100644
--- a/drivers/pci/vpd.c
+++ b/drivers/pci/vpd.c
@@ -540,6 +540,7 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_LSI_LOGIC, 0x002f, quirk_blacklist_vpd);
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_LSI_LOGIC, 0x005d, quirk_blacklist_vpd);
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_LSI_LOGIC, 0x005f, quirk_blacklist_vpd);
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ATTANSIC, PCI_ANY_ID, quirk_blacklist_vpd);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_SAMSUNG, 0xa800, quirk_blacklist_vpd);
 /*
  * The Amazon Annapurna Labs 0x0031 device id is reused for other non Root Port
  * device types, so the quirk is registered for the PCI_CLASS_BRIDGE_PCI class.
-- 
2.33.0