On Wed, 2021-09-01 at 18:51 +0200, Heiner Kallweit wrote: > On 01.09.2021 17:51, Pali Rohár wrote: > > On Wednesday 01 September 2021 16:01:54 Jonas Dreßler wrote: > > > On 8/30/21 2:49 PM, Andy Shevchenko wrote: > > > > On Mon, Aug 30, 2021 at 3:38 PM Jonas Dreßler <verdre@xxxxxxx> wrote: > > > > > > > > > > On the 88W8897 card it's very important the TX ring write pointer is > > > > > updated correctly to its new value before setting the TX ready > > > > > interrupt, otherwise the firmware appears to crash (probably because > > > > > it's trying to DMA-read from the wrong place). > > > > > > > This sounds somehow like the typical case where you write DMA descriptors > and then ring the doorbell. This normally requires a dma_wmb(). > Maybe something like that is missing here? But it looks like this "TX ring write pointer" is actually the register? However, I would agree that doing it in mwifiex_write_reg() is possibly too big a hammer - could be done only for reg->tx_wrptr, not all the registers? Actually, can two writes actually cross on PCI? johannes
