On Thu, 2023-09-21 at 13:24 -0400, Antoine Beaupré wrote:
> Hi,
>
> I've found what I feel might be a regression between Linux 6.1 and
> 6.5. For other reasons, I upgraded the kernel on my Debian 12
> ("bookworm", stale) laptop from the distribution 6.1.52 to the unstable
> ("sid") version, 6.5.3.
>
> After the upgrade, I started to notice stuttering in my audio player, I
> tracked it down and managed to correlate it with some kernel errors
> related to the iwlwifi driver.
>
> What's interesting is that this happens regardless of whether or not the
> NIC is connected to a network. In at least one of the traces, the
> computer was connected over a wire and wireless was not associated in
> Network Manager.
This happens when scanning.
> Here's an example of the problem:
>
> sep 21 09:33:14 angela kernel: iwlwifi 0000:a6:00.0: Microcode SW error detected. Restarting 0x0.
Can you give a few wpa_supplicant lines (there were some below) above
this? Just want to make sure it really is scanning on wlan0, not
something with P2P device.
> sep 21 09:33:14 angela kernel: iwlwifi 0000:a6:00.0: 0x20103600 | ADVANCED_SYSASSERT
> sep 21 09:33:14 angela kernel: iwlwifi 0000:a6:00.0: 0x000000FF | umac data1
This means that somehow scan_start_mac_or_link_id in the driver ended up
0xff which is invalid, but I'm not sure I see immediately how that
happened, since it looks like in 6.5.3 we do assign it reasonably. I
guess somehow in the code link_info->fw_link_id must be 0xff (invalid
ID), but I'm not sure I see how that could happen.
*thinks*
Oh.. This is an older firmware, so it doesn't have
IWL_UCODE_TLV_CAPA_MLD_API_SUPPORT! Hah. I feel like I had some concerns
in this area before ... but maybe the other way around.
I think something like this, perhaps:
--- a/drivers/net/wireless/intel/iwlwifi/mvm/scan.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/scan.c
@@ -2342,7 +2342,7 @@ iwl_mvm_scan_umac_fill_general_p_v12(struct iwl_mvm *mvm,
if (gen_flags & IWL_UMAC_SCAN_GEN_FLAGS_V2_FRAGMENTED_LMAC2)
gp->num_of_fragments[SCAN_HB_LMAC_IDX] = IWL_SCAN_NUM_OF_FRAGS;
- if (version < 12) {
+ if (version < 12 || !iwl_mvm_has_mld_api(mvm->fw)) {
gp->scan_start_mac_or_link_id = scan_vif->id;
} else {
struct iwl_mvm_vif_link_info *link_info;
johannes
