[Buildroot] [PATCH] package/i2c-tools: add upstream post-4.2 i2ctransfer fix

[Baruch Siach <baruch@tkos.co.il>]

Hi Peter,

On Sat, Apr 10 2021, Peter Korsgaard wrote:

> i2c-tools 4.2 contained an invalid check, leading to verbose false-positive
> warning messages when the variable length ({r,w}?) option is used:
>
> https://www.spinics.net/lists/linux-i2c/msg50032.html

Maybe also add a link to Jean's response:

  https://www.spinics.net/lists/linux-i2c/msg50253.html

> Unfortunately upstream does not make bugfix releases, instead opting to list
> such bugfixes on the wiki:
>
> https://i2c.wiki.kernel.org/index.php/I2C_Tools
>
> So add the patch here.
>
> Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

Acked-by: Baruch Siach <baruch@tkos.co.il>

Thanks,
baruch

> ---
>  ...transfer-add-check-for-returned-leng.patch | 41 +++++++++++++++++++
>  1 file changed, 41 insertions(+)
>  create mode 100644 package/i2c-tools/0001-Revert-tools-i2ctransfer-add-check-for-returned-leng.patch
>
> diff --git a/package/i2c-tools/0001-Revert-tools-i2ctransfer-add-check-for-returned-leng.patch b/package/i2c-tools/0001-Revert-tools-i2ctransfer-add-check-for-returned-leng.patch
> new file mode 100644
> index 0000000000..7173efe219
> --- /dev/null
> +++ b/package/i2c-tools/0001-Revert-tools-i2ctransfer-add-check-for-returned-leng.patch
> @@ -0,0 +1,41 @@
> +From 06a1909ae1e8ae1edc70dc48dd22a32ba5eceecb Mon Sep 17 00:00:00 2001
> +From: Wolfram Sang <wsa+renesas@sang-engineering.com>
> +Date: Tue, 9 Feb 2021 12:05:56 +0100
> +Subject: [PATCH] Revert "tools: i2ctransfer: add check for returned length
> + from driver"
> +
> +This reverts commit 34806fc4e7090b34e32fa1110d546ab5ce01a6a0. It was
> +developed against an experimental kernel. The regular kernel does not
> +update the new message length to userspace, so the check is always false
> +positive. We can't change the kernel behaviour because it would break
> +the ABI. So revert this commit.
> +
> +Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> +Signed-off-by: Wolfram Sang <wsa@kernel.org>
> +[Peter: drop CHANGES update]
> +Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
> +---
> + tools/i2ctransfer.c | 7 +------
> + 1 file changed, 1 insertions(+), 6 deletions(-)
> +
> +diff --git a/tools/i2ctransfer.c b/tools/i2ctransfer.c
> +index f2a4df8..b0e8d43 100644
> +--- a/tools/i2ctransfer.c
> ++++ b/tools/i2ctransfer.c
> +@@ -88,12 +88,7 @@ static void print_msgs(struct i2c_msg *msgs, __u32 nmsgs, unsigned flags)
> + 		int recv_len = msgs[i].flags & I2C_M_RECV_LEN;
> + 		int print_buf = (read && (flags & PRINT_READ_BUF)) ||
> + 				(!read && (flags & PRINT_WRITE_BUF));
> +-		__u16 len = msgs[i].len;
> +-
> +-		if (recv_len && print_buf && len != msgs[i].buf[0] + 1) {
> +-			fprintf(stderr, "Correcting wrong msg length after recv_len! Please fix the I2C driver and/or report.\n");
> +-			len = msgs[i].buf[0] + 1;
> +-		}
> ++		__u16 len = recv_len ? msgs[i].buf[0] + 1 : msgs[i].len;
> + 
> + 		if (flags & PRINT_HEADER) {
> + 			fprintf(output, "msg %u: addr 0x%02x, %s, len ",
> +-- 
> +2.20.1
> +


-- 
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