On Thursday 23 February 2012 09:34 PM, Tom Warren wrote:
Puneet,
-----Original Message----- From: Puneet Saxena Sent: Thursday, February 23, 2012 7:25 AM To: u-boot@lists.denx.de; sjg@chromium.org Cc: vapier@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 Saxenapuneets@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@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
My thought of adding "#define USB_QUIRK_STRING_FETCH_255 0x00000001" instead "#define USB_QUIRK_STRING_FETCH_255" is, some time in future we might have to implement kernel quirk kind of functionality to make generic implementation. Its not needed as of now. Will incorporate in next patch.
Thanks, Puneet
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