Re: [PATCH 4.14 04/40] Bluetooth: btqca: Add a short delay before downloading the NVM

Matthias Kaehlcke
2019-09-09T16:14:07Z

On Sun, Sep 08, 2019 at 01:41:37PM +0100, Greg Kroah-Hartman wrote:
> [ Upstream commit 8059ba0bd0e4694e51c2ee6438a77b325f06c0d5 ]
>
> 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

WC3990 support was only added in 4.19, so this shouldn't be needed in
older kernels, but it shouldn't do any harm either ;-)

> 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@chromium.org>
> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
> drivers/bluetooth/btqca.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/bluetooth/btqca.c b/drivers/bluetooth/btqca.c
> index 0bbdfcef2aa84..a48a61f22f823 100644
> --- a/drivers/bluetooth/btqca.c
> +++ b/drivers/bluetooth/btqca.c
> @@ -363,6 +363,9 @@ int qca_uart_setup_rome(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;
> snprintf(config.fwname, sizeof(config.fwname), "qca/nvm_%08x.bin",