[U-Boot] [PATCH 2/2] usb: Add quirk "USB_QUIRK_STRING_FETCH_255"

Tom Warren
2012-02-23T16:04:05Z

Puneet,

> -----Original Message-----
> From: Puneet Saxena
> Sent: Thursday, February 23, 2012 7:25 AM
> To: u-boot at lists.denx.de; sjg at chromium.org
> Cc: vapier at gentoo.org; Tom Warren; Puneet Saxena
> Subject: [PATCH 2/2] usb: Add quirk "USB_QUIRK_STRING_FETCH_255"
>
> Add a quirk "USB_QUIRK_STRING_FETCH_255", borrowed from Linux kernel to
> fetch string using descriptor length then fetch actual bytes returned in
> descriptor buffer.
>
> Signed-off-by: Puneet Saxena <puneets@nvidia.com>
> ---
> Changes for v2:
> - Add quirk for fetching actual bytes
>
> common/usb.c | 4 ++++
> include/configs/tegra2-common.h | 7 +++++++
> 2 files changed, 11 insertions(+), 0 deletions(-)
>
> diff --git a/common/usb.c b/common/usb.c index 75926aa..cd85c18 100644
> --- a/common/usb.c
> +++ b/common/usb.c
> @@ -660,7 +660,11 @@ static int usb_string_sub(struct usb_device *dev,
> unsigned int langid,
>
> /* Try to read the string descriptor by asking for the maximum
> * possible number of bytes */
> +#ifdef USB_QUIRK_STRING_FETCH_255
> + rc = -4;
> +#else
> rc = usb_get_string(dev, langid, index, buf, 255);
> +#endif
>
> /* If that failed try to read the descriptor length, then
> * ask for just that many bytes */
> diff --git a/include/configs/tegra2-common.h b/include/configs/tegra2-
> common.h index 266d0e5..51cc200 100644
> --- a/include/configs/tegra2-common.h
> +++ b/include/configs/tegra2-common.h
> @@ -172,4 +172,11 @@
>
> #define CONFIG_TEGRA2_GPIO
> #define CONFIG_CMD_GPIO
> +
> +/*
> + * Imported the quirk from Linux kernel */
> +/* string descriptors must not be fetched using a 255-byte read */
> +#define USB_QUIRK_STRING_FETCH_255 0x00000001
> +
> #endif /* __TEGRA2_COMMON_H */
> --
> 1.7.1

Make sure you include the USB custodian/expert when submitting USB patches (Remy Bohmer, linux at bohmer.net). Also, as TomR says, this should be a CONFIG_USB_QUIRK_xxx string. Note that it doesn't need a 0x00000001 - #define'ing a switch means it's explicitly enabled - no need for 1 or 0 (see all the other CONFIG_ defines in the config headers).

Tom

--
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