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| author |   Gautam Menghani <gautam@linux.ibm.com> | 2025-03-05 14:32:36 +0530 |
|---|---|---|
| committer |   Madhavan Srinivasan <maddy@linux.ibm.com> | 2025-04-29 11:07:45 +0530 |
| commit | 9cc0eafd28c7faef300822992bb08d79cab2a36c (patch) | |
| tree | fca3877ac9d1467951b815e8e9ebe2e7a67e23ff /include/uapi/linux/android/ssh:/git@git.zx2c4.com | |
| parent | powerpc/bpf: fix JIT code size calculation of bpf trampoline (diff) | |
powerpc/pseries/msi: Avoid reading PCI device registers in reduced power states
When a system is being suspended to RAM, the PCI devices are also
suspended and the PPC code ends up calling pseries_msi_compose_msg() and
this triggers the BUG_ON() in __pci_read_msi_msg() because the device at
this point is in reduced power state. In reduced power state, the memory
mapped registers of the PCI device are not accessible.
To replicate the bug:
1. Make sure deep sleep is selected
# cat /sys/power/mem_sleep
s2idle [deep]
2. Make sure console is not suspended (so that dmesg logs are visible)
echo N > /sys/module/printk/parameters/console_suspend
3. Suspend the system
echo mem > /sys/power/state
To fix this behaviour, read the cached msi message of the device when the
device is not in PCI_D0 power state instead of touching the hardware.
Fixes: a5f3d2c17b07 ("powerpc/pseries/pci: Add MSI domains")
Cc: stable@vger.kernel.org # v5.15+
Signed-off-by: Gautam Menghani <gautam@linux.ibm.com>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Reviewed-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20250305090237.294633-1-gautam@linux.ibm.com
Diffstat (limited to 'include/uapi/linux/android/ssh:/git@git.zx2c4.com')
0 files changed, 0 insertions, 0 deletions