Re: [RFC PATCH 00/17] Drop uses of pci_read_config_*() return value
From: Christoph Hellwig <hch@infradead.org>
Date: 2020-08-03 06:57:04
Also in:
dmaengine, intel-gfx, linux-crypto, linux-edac, linux-fpga, linux-gpio, linux-hwmon, linux-i2c, linux-ide, linux-iommu, linux-kernel-mentees, linux-pci, linux-rdma, linux-wireless, lkml
On Sun, Aug 02, 2020 at 02:14:06PM -0500, Bjorn Helgaas wrote:
But what guarantees that a PCI config register cannot contain ~0? If there's something about that in the spec I'd love to know where it is because it would simplify a lot of things.
There isn't. An we even have cases like the NVMe controller memory buffer and persistent memory region, which are BARs that store abritrary values for later retreival, so it can't. (now those features have a major issue with error detection, but that is another issue)