On Wed, Sep 8, 2021 at 12:07 AM Marek Behún marek.behun@nic.cz wrote:
From: Pali Rohár pali@kernel.org
Some PCIe controller's read_config() method support indicating error directly via return value, but some cannot distinguish all-ones (or all-zeros) read response from an error.
The current code in pci_bind_bus_devices() interprets all-ones / all-zeros in PCI_VENDOR_ID register as "nothing connected", and continues the cycle, but an error returned via return value breaks the cycle.
This is wrong for the PCIe controllers which return this error via return value.
Handle all errors when reading PCI_VENDOR_ID the same way.
This fixes enumeration of PCI devices for example when there is a PCI bridge connected behind another PCI bridge and not all ports are connected to a device, and the controller (for example Aardvark) translates the UR error (Unsupported Request) as -EOPNOTSUPP.
Signed-off-by: Pali Rohár pali@kernel.org Signed-off-by: Marek Behún marek.behun@nic.cz
drivers/pci/pci-uclass.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-)
Is it possible to update these PCI controller drivers to fill in vendor id to all zeros when there is an errror?
Regards, Bin