[Qemu-devel] Re: [PATCH, RESEND] usb: increase buffer for USB control requests

[Michael S. Tsirkin]

On Sun, Jan 24, 2010 at 05:34:52PM +0100, Christian Krause wrote:
> Resend. The patch was already sent to the list on 2009-12-11. It would
> be great if it could be reviewed and applied. Thank you very much
> in advance.
> 
> The WLAN USB stick ZyXEL NWD271N (0586:3417) uses very large
> usb control transfers of more than 2048 bytes which won't fit
> into the buffer of the ctrl_struct. This results in an error message
> "husb: ctrl buffer too small" and a non-working device.
> Increasing the buffer size to 8192 seems to be a safe choice.
> 
> Signed-off-by: Christian Krause <address@hidden>

Are there any drawbacks to make\ing the buffer larger?
If no, let's just make it 64K? IIUC that's a maximum
length for control transfers as length is a 16 bit field.


> ---
>  usb-linux.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/usb-linux.c b/usb-linux.c
> index 285ac22..d205bd3 100644
> --- a/usb-linux.c
> +++ b/usb-linux.c
> @@ -113,7 +113,7 @@ struct ctrl_struct {
>      uint16_t offset;
>      uint8_t  state;
>      struct   usb_ctrlrequest req;
> -    uint8_t  buffer[2048];
> +    uint8_t  buffer[8192];
>  };
>  
>  struct USBAutoFilter {
> -- 
> 1.6.2.5
> 
>