On Tue, Aug 27, 2024 at 06:48:45PM -0500, Bjorn Helgaas wrote: > From: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > > After a device reset, pci_dev_wait() waits for a device to become > completely ready by polling the PCI_COMMAND register. The spec envisions > that software would instead poll for the device to stop responding to > config reads with Completions with Request Retry Status (RRS). > > Polling PCI_COMMAND leads to hardware retries that are invisible to > software and the backoff between software retries doesn't work correctly. > > Root Ports are not required to support the Configuration RRS Software > Visibility feature that prevents hardware retries and makes the RRS > Completions visible to software, so this series only uses it when available > and falls back to PCI_COMMAND polling when it's not. > > This is completely untested and posted for comments. > > Bjorn Helgaas (3): > PCI: Wait for device readiness with Configuration RRS > PCI: aardvark: Correct Configuration RRS checking > PCI: Rename CRS Completion Status to RRS > > drivers/bcma/driver_pci_host.c | 10 ++-- > drivers/pci/controller/dwc/pcie-tegra194.c | 18 +++--- > drivers/pci/controller/pci-aardvark.c | 64 +++++++++++----------- > drivers/pci/controller/pci-xgene.c | 6 +- > drivers/pci/controller/pcie-iproc.c | 18 +++--- > drivers/pci/pci-bridge-emul.c | 4 +- > drivers/pci/pci.c | 41 +++++++++----- > drivers/pci/pci.h | 11 +++- > drivers/pci/probe.c | 33 +++++------ > include/linux/bcma/bcma_driver_pci.h | 2 +- > include/linux/pci.h | 1 + > include/uapi/linux/pci_regs.h | 6 +- > 12 files changed, 117 insertions(+), 97 deletions(-) I provisionally applied this on pci/crs for v6.12. Please let me know of any concerns. I do have one internal test report, but more would be better since I know this affects many devices. Bjorn
