From: Jonas Dreßler verdre@v0yd.nl
commit e5f4eb8223aa740237cd463246a7debcddf4eda1 upstream.
On the 88W8897 PCIe+USB card the firmware randomly crashes after setting the TX ring write pointer. The issue is present in the latest firmware version 15.68.19.p21 of the PCIe+USB card.
Those firmware crashes can be worked around by reading any PCI register of the card after setting that register, so read the PCI_VENDOR_ID register here. The reason this works is probably because we keep the bus from entering an ASPM state for a bit longer, because that's what causes the cards firmware to crash.
This fixes a bug where during RX/TX traffic and with ASPM L1 substates enabled (the specific substates where the issue happens appear to be platform dependent), the firmware crashes and eventually a command timeout appears in the logs.
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=109681 Cc: stable@vger.kernel.org Signed-off-by: Jonas Dreßler verdre@v0yd.nl Signed-off-by: Kalle Valo kvalo@codeaurora.org Link: https://lore.kernel.org/r/20211011133224.15561-2-verdre@v0yd.nl Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/wireless/mwifiex/pcie.c | 8 ++++++++ 1 file changed, 8 insertions(+)
--- a/drivers/net/wireless/mwifiex/pcie.c +++ b/drivers/net/wireless/mwifiex/pcie.c @@ -1210,6 +1210,14 @@ mwifiex_pcie_send_data(struct mwifiex_ad ret = -1; goto done_unmap; } + + /* The firmware (latest version 15.68.19.p21) of the 88W8897 PCIe+USB card + * seems to crash randomly after setting the TX ring write pointer when + * ASPM powersaving is enabled. A workaround seems to be keeping the bus + * busy by reading a random register afterwards. + */ + mwifiex_read_reg(adapter, PCI_VENDOR_ID, &rx_val); + if ((mwifiex_pcie_txbd_not_full(card)) && tx_param->next_pkt_len) { /* have more packets and TxBD still can hold more */