[PATCH v2] PCI/VPD: Silence warning if optional VPD PROM is missing

[Heiner Kallweit <hkallweit1@gmail.com>]

Realtek RTL8169/8168/8125 NIC families indicate VPD capability and an
optional VPD EEPROM can be connected via I2C/SPI. However I haven't
seen any card or system with such a VPD EEPROM yet. The missing EEPROM
causes the following warning whenever e.g. lscpi -vv is executed.

invalid short VPD tag 00 at offset 01

The warning confuses users, I think we should handle the situation more
gentle. Therefore, if first VPD byte is read as 0x00, assume a missing
optional VPD PROM and replace the warning with a more descriptive
message at info level.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
v2: - don't remove user info completely, replace the warning with a more
      message at info level
---
 drivers/pci/vpd.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/pci/vpd.c b/drivers/pci/vpd.c
index d1cbc5e64..48f4a9ae8 100644
--- a/drivers/pci/vpd.c
+++ b/drivers/pci/vpd.c
@@ -74,6 +74,11 @@ static size_t pci_vpd_size(struct pci_dev *dev, size_t old_size)
 	       pci_read_vpd(dev, off, 1, header) == 1) {
 		unsigned char tag;
 
+		if (!header[0] && !off) {
+			pci_info(dev, "Invalid VPD tag 00, assume missing optional VPD EPROM\n");
+			return 0;
+		}
+
 		if (header[0] & PCI_VPD_LRDT) {
 			/* Large Resource Data Type Tag */
 			tag = pci_vpd_lrdt_tag(header);
-- 
2.31.1