On WCN3990 downloading the NVM sometimes fails with a "TLV response size mismatch" error:
[ 174.949955] Bluetooth: btqca.c:qca_download_firmware() hci0: QCA Downloading qca/crnv21.bin [ 174.958718] Bluetooth: btqca.c:qca_tlv_send_segment() hci0: QCA TLV response size mismatch It seems the controller needs a short time after downloading the firmware before it is ready for the NVM. A delay as short as 1 ms seems sufficient, make it 10 ms just in case. No event is received during the delay, hence we don't just silently drop an extra event. Signed-off-by: Matthias Kaehlcke <[email protected]> --- I'm only guessing why the delay is needed, maybe QCA folks can shed more light on this. I didn't see this error when testing 2faa3f15fa2f ("Bluetooth: hci_qca: wcn3990: Drop baudrate change vendor event") and 32646db8cc28 ("Bluetooth: btqca: inject command complete event during fw download") intensively a few months ago. My guess is that some changes in the kernel (I test with a 4.19 kernel with regular -stable merges) altered the timing, which made this issue visible. --- drivers/bluetooth/btqca.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/bluetooth/btqca.c b/drivers/bluetooth/btqca.c index 8b33128dccee..c59ca5782b63 100644 --- a/drivers/bluetooth/btqca.c +++ b/drivers/bluetooth/btqca.c @@ -388,6 +388,9 @@ int qca_uart_setup(struct hci_dev *hdev, uint8_t baudrate, return err; } + /* Give the controller some time to get ready to receive the NVM */ + msleep(10); + /* Download NVM configuration */ config.type = TLV_TYPE_NVM; if (firmware_name) -- 2.22.0.410.gd8fdbe21b5-goog
