diff options
| author | Johannes Berg <johannes.berg@intel.com> | 2023-09-21 11:58:03 +0300 |
|---|---|---|
| committer | Johannes Berg <johannes.berg@intel.com> | 2023-09-25 09:14:59 +0200 |
| commit | 54d1e8b27e8652c369d0e70eda3ea38b97836c1d (patch) | |
| tree | 2a69b98bdfd1f9365bdd2c8c80ba024eb5aefe11 /drivers | |
| parent | 2f199ba8776adb5e6e138559acd88f508193cf37 (diff) | |
wifi: iwlwifi: pcie: (re-)assign BAR0 on driver bind
There's a race with runtime PM getting enabled by userspace:
- we rescan the PCI bus
- this creates the new PCI device including its sysfs
representation
- udev sees the new device, and the (OS-specific?) scripting
enables runtime PM by writing to power/control; this can
happen _before_ the next step - this will runtime-suspend
the device which saves the config space, including the BAR0
that wasn't assigned yet
- the bus rescan assigns resources to the devices and writes
them to the config space of the device
(but not the runtime-pm saved copy)
- the driver binds and this disallows runtime PM, so the device
is resumed, restoring the (incomplete!) config space
- the driver cannot work due to BAR0 not being configured
Fixing the actual race is hard and deep in the PCI layer,
though probably should be done for upstream as well; perhaps
runtime PM should only be allowed after resource assignment,
or some other TBD way.
Work around this in the driver for now by simply (re-)assigning
BAR0 when the driver initializes, if it's unset.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230921110726.5f5f782a4e97.I4b7bf5c52ba44a8c7f9878009021689bbfa9c5ef@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/net/wireless/intel/iwlwifi/pcie/trans.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c index 849ea1851508..5020ae4493c6 100644 --- a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c +++ b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c @@ -3610,10 +3610,19 @@ struct iwl_trans *iwl_trans_pcie_alloc(struct pci_dev *pdev, int ret, addr_size; const struct iwl_trans_ops *ops = &trans_ops_pcie_gen2; void __iomem * const *table; + u32 bar0; if (!cfg_trans->gen2) ops = &trans_ops_pcie; + /* reassign our BAR 0 if invalid due to possible runtime PM races */ + pci_read_config_dword(pdev, PCI_BASE_ADDRESS_0, &bar0); + if (bar0 == PCI_BASE_ADDRESS_MEM_TYPE_64) { + ret = pci_assign_resource(pdev, 0); + if (ret) + return ERR_PTR(ret); + } + ret = pcim_enable_device(pdev); if (ret) return ERR_PTR(ret); |