Re: [PATCH v4 1/5] tools: iio: iio_generic_buffer ensure alignment

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Wed, Sep 27, 2023 at 11:26:07AM +0300, Matti Vaittinen wrote:
> The iio_generic_buffer can return garbage values when the total size of
> scan data is not a multiple of the largest element in the scan. This can be
> demonstrated by reading a scan, consisting, for example of one 4-byte and
> one 2-byte element, where the 4-byte element is first in the buffer.
> 
> The IIO generic buffer code does not take into account the last two
> padding bytes that are needed to ensure that the 4-byte data for next
> scan is correctly aligned.
> 
> Add the padding bytes required to align the next sample with the scan size.

...

> +	/*
> +	 * We wan't the data in next sample to also be properly aligned so

Pardon me, won't or want, I didn't get?..

> +	 * we'll add padding at the end if needed.
> +	 *
> +	 * Please note, this code does ensure alignment to maximum channel
> +	 * size. It works only as long as the channel sizes are 1, 2, 4 or 8
> +	 * bytes. Also, on 32 bit platforms it might be enough to align also

32-bit

> +	 * the 8 byte elements to 4 byte boundary - which this code is not

8-byte
4-byte

> +	 * doing.
> +	 */

-- 
With Best Regards,
Andy Shevchenko