fae0e055d0
[ Upstream commit 6613443ffc49d03e27f0404978f685c4eac43fba ]
On runtime resume, pci_dev_wait() is called:
pci_pm_runtime_resume()
pci_pm_bridge_power_up_actions()
pci_bridge_wait_for_secondary_bus()
pci_dev_wait()
While a device is runtime suspended along with its PCI hierarchy, the
device could get disconnected. In such case, the link will not come up no
matter how long pci_dev_wait() waits for it.
Besides the above mentioned case, there could be other ways to get the
device disconnected while pci_dev_wait() is waiting for the link to come
up.
Make pci_dev_wait() exit if the device is already disconnected to avoid
unnecessary delay.
The use cases of pci_dev_wait() boil down to two:
1. Waiting for the device after reset
2. pci_bridge_wait_for_secondary_bus()
The callers in both cases seem to benefit from propagating the
disconnection as error even if device disconnection would be more
analoguous to the case where there is no device in the first place which
return 0 from pci_dev_wait(). In the case 2, it results in unnecessary
marking of the devices disconnected again but that is just harmless extra
work.
Also make sure compiler does not become too clever with dev->error_state
and use READ_ONCE() to force a fetch for the up-to-date value.
Link: https://lore.kernel.org/r/20240208132322.4811-1-ilpo.jarvinen@linux.intel.com
Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
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.