Hi Fabio,
On Thu, Jan 7, 2016 at 9:31 PM, Fabio Estevam festevam@gmail.com wrote:
On Thu, Jan 7, 2016 at 10:58 AM, Bin Meng bmeng.cn@gmail.com wrote:
Ah, yes! Sorry I wanted to say the original proposal to "return 0" instead. But now I failed to understand why this fixed the issue because those error numbers are not zero.
The problem only happens if we return a negative value.
OK, now I am pretty sure this fix is not correct, that "the problem only happens if we return a negative value".
The imx and layerscape PCIe driver registers PCI config ops as following:
pci_set_ops(hose, pci_hose_read_config_byte_via_dword, pci_hose_read_config_word_via_dword, ls_pcie_read_config, pci_hose_write_config_byte_via_dword, pci_hose_write_config_word_via_dword, ls_pcie_write_config);
The pci_hose_read_config_byte_via_dword() and pci_hose_read_config_word_via_dword() only return -1 if the error number < 0. What if I call:
u32 data; ret = pci_read_config_dword(dev, PCI_VENDOR_ID, &data);
This will fail with error number 0x86, but if we do:
u16 data; ret = pci_read_config_dword(dev, PCI_VENDOR_ID, &data);
This will _not_ fail. This is inconsistent. You are just trying to workaround the 'pciinfo' command to make it output no error message.
And why returning zero is bad? From a working PCIe controller (either
It is not bad, but I still prefer to keep in sync with the kernel driver.
Regards, Bin