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 <mka@xxxxxxxxxxxx>
---
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
