Hi,
Bjorn Helgaas helgaas@kernel.org writes:
802b7c06adc7 replaced cns3xxx_pci_write_config(), which always used __raw_writel() so it only did 32-bit accesses, with pci_generic_config_write(), which uses writeb/writew/writel() depending on the size.
802b7c06adc7 also converted cns3xxx_pci_read_config() from always using __raw_readl() (a 32-bit access) to using pci_generic_config_read32(), which also always does a 32-bit access.
This makes me think the cnx3xxx hardware is only capable of 32-bit accesses, and this patch should change the driver to use pci_generic_config_write32() instead of pci_generic_config_write() in addition to the mapping fix above.
Hasn't it already been verified that the CNS3xxx can do 8-bit accesses (and probably 16-bit ones as well), and that the docs don't mention any such limitation?
I don't think hardware that only supports 32-bit PCI writes can be quite spec-compliant (see the comments in pci_generic_config_write32()). So (1) you may see an additional dmesg warning when you convert to use it, and (2) it's possible that there may still be instability related to the corruption caused by using a 32-bit write when an 8-bit write was intended.
Right. I think IDE/SATA controllers are affected, for example.