On Thu, Oct 24, 2019 at 11:01:48AM +0200, Lorenzo Bianconi wrote: > > On Thu, Oct 24, 2019 at 12:23:16AM +0200, Lorenzo Bianconi wrote: > > > mt76 dma layer is supposed to unmap skb data buffers while keep txwi > > > mapped on hw dma ring. At the moment mt76 wrongly unmap txwi or does > > > not unmap data fragments in even positions for non-linear skbs. This > > > issue may result in hw hangs with A-MSDU if the system relies on IOMMU > > > or SWIOTLB. Fix this behaviour properly unmapping data fragments on > > > non-linear skbs. > > > > If we have to keep txwi mapped, before unmap fragments, when then > > txwi is unmaped ? > > txwi are mapped when they are crated in mt76_alloc_txwi(). Whenever we need to > modify them we sync the DMA in mt76_dma_tx_queue_skb(). txwi are unmapped in > mt76_tx_free() at driver unload. So not only txwi is wrongly unmapped on runtime, but we can call dma_sync_single_for_cpu/device() after dma_unmap_single(). That serious bug, good you spotted it and fixed! Stanislaw
