Emmanuel Grumbach <emmanuel.grumbach@xxxxxxxxx> wrote: > 22000 devices (previously referenced as A000) can support > short transmit queues. This means that we have less DMA > descriptors (TFD) for those shorter queues. > Previous devices must still have 256 TFDs for each queue > even if those 256 TFDs point to fewer buffers. > > When I introduced support for the short queues for 22000 > I broke older devices by assuming that they can also have > less TFDs in their queues. This led to several problems: > > 1) the payload of the commands weren't unmapped properly > which caused the SWIOTLB to complain at some point. > 2) the hardware could get confused and we get hardware > crashes. > > The corresponding bugzilla entries are: > > https://bugzilla.kernel.org/show_bug.cgi?id=198201 > https://bugzilla.kernel.org/show_bug.cgi?id=198265 > > Cc: stable@xxxxxxxxxxxxxxx # 4.14+ > Fixes: 4ecab5616023 ("iwlwifi: pcie: support short Tx queues for A000 device family") > Reviewed-by: Sharon, Sara <sara.sharon@xxxxxxxxx> > Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@xxxxxxxxx> Patch applied to wireless-drivers.git, thanks. 943309d4aad6 iwlwifi: pcie: fix DMA memory mapping / unmapping -- https://patchwork.kernel.org/patch/10143989/ https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches