821cdad5c4
Sporadic reset issues have been observed with an Intel 750 NVMe drive while
assigning the physical function to the guest machine. The sequence of
events observed is as follows:
- perform a Function Level Reset (FLR)
- sleep up to 1000ms total
- read ~0 from PCI_COMMAND (CRS completion for config read)
- warn that the device didn't return from FLR
- touch the device before it's ready
- device drops config writes when we restore register settings (there's
no mechanism for software to learn about CRS completions for writes)
- incomplete register restore leaves device in inconsistent state
- device probe fails because device is in inconsistent state
After reset, an endpoint may respond to config requests with Configuration
Request Retry Status (CRS) to indicate that it is not ready to accept new
requests. See PCIe r3.1, sec 2.3.1 and 6.6.2.
Increase the timeout value from 1 second to 60 seconds to cover the period
where device responds with CRS and also report polling progress.
Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
[bhelgaas: include the mandatory 100ms in the delays we print]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.