> -----Original Message-----
> From: Bitterblue Smith <rtl8821cerfe2@xxxxxxxxx>
> Sent: Thursday, January 18, 2024 11:56 PM
> To: Ping-Ke Shih <pkshih@xxxxxxxxxxx>; linux-wireless@xxxxxxxxxxxxxxx
> Cc: Larry Finger <Larry.Finger@xxxxxxxxxxxx>
> Subject: Re: [PATCH v2] wifi: rtlwifi: Speed up firmware loading for USB
>
>
> On 18/01/2024 02:37, Ping-Ke Shih wrote:
> >
> >
> >> -----Original Message-----
> >> From: Bitterblue Smith <rtl8821cerfe2@xxxxxxxxx>
> >> Sent: Thursday, January 18, 2024 4:12 AM
> >> To: linux-wireless@xxxxxxxxxxxxxxx
> >> Cc: Ping-Ke Shih <pkshih@xxxxxxxxxxx>; Larry Finger <Larry.Finger@xxxxxxxxxxxx>
> >> Subject: [PATCH v2] wifi: rtlwifi: Speed up firmware loading for USB
> >>
> >> +static void _usb_write_chunk_sync(struct rtl_priv *rtlpriv, u32 addr,
> >> + u32 length, u8 *data)
> >> +{
> >> + struct usb_device *udev = to_usb_device(rtlpriv->io.dev);
> >> +
> >> + _usbctrl_vendorreq_sync(udev, REALTEK_USB_VENQT_WRITE, addr, data, length);
> >
> > Just curious. Originally, it uses 1/2/4 as length for write8/16/32, and this
> > patch additionally uses 8/64 as length. Any limitation of argument 'length' of
> > this function? Is arbitrary number disallowed?
> >
>
> I didn't find anything in the usb_control_msg() documentation.
> I only found this issue, where some people say 0xffff is fine,
> but older hardware may have a limit of 4096:
> https://github.com/libusb/libusb/issues/125
>
> rtl8xxxu uses lengths of 32, 94, 124, 126, 128, 156, 254 bytes.
> Some other Realtek wifi drivers use 196 bytes.
Got it. Thanks for the information.
