summaryrefslogtreecommitdiff
path: root/drivers/pci
diff options
context:
space:
mode:
authorBjorn Helgaas <bhelgaas@google.com>2022-10-05 05:58:08 +0300
committerBjorn Helgaas <bhelgaas@google.com>2022-10-05 20:11:56 +0300
commitcfc0028627cadfa271fab0290f18731193d63d87 (patch)
tree538fcbf073e7c0919c2c81898c2b8836ee6ebfa9 /drivers/pci
parent9e2a03173d1b4544c1113059e61e3caa7ce5e3a4 (diff)
downloadlinux-cfc0028627cadfa271fab0290f18731193d63d87.tar.xz
PCI/ASPM: Ignore L1 PM Substates if device lacks capability
187f91db8237 ("PCI/ASPM: Remove struct aspm_register_info.l1ss_cap") inadvertently removed a check for existence of the L1 PM Substates (L1SS) Capability before reading it. If there is no L1SS Capability, this means we mistakenly read PCI_COMMAND and PCI_STATUS (config address 0x04) and interpret that as the PCI_L1SS_CAP register, so we may incorrectly configure L1SS. Make sure the L1SS Capability exists before trying to read it. Fixes: 187f91db8237 ("PCI/ASPM: Remove struct aspm_register_info.l1ss_cap") Link: https://lore.kernel.org/r/20221005025809.2247547-3-helgaas@kernel.org Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Diffstat (limited to 'drivers/pci')
-rw-r--r--drivers/pci/pcie/aspm.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 4535228e4a64..f12d117f44e0 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -560,6 +560,9 @@ static void aspm_l1ss_init(struct pcie_link_state *link)
u32 parent_l1ss_cap, child_l1ss_cap;
u32 parent_l1ss_ctl1 = 0, child_l1ss_ctl1 = 0;
+ if (!parent->l1ss || !child->l1ss)
+ return;
+
/* Setup L1 substate */
pci_read_config_dword(parent, parent->l1ss + PCI_L1SS_CAP,
&parent_l1ss_cap);