Re: [PATCH v1 3/3] iio: hid-sensor: Use aligned data type for timestamp

On Mon, Aug 28, 2023 at 05:09:28PM +0100, Jonathan Cameron wrote:

On Tue, 15 Aug 2023 18:40:27 +0300
Andy Shevchenko [off-list ref] wrote:

...

quoted

-	/* Ensure timestamp is naturally aligned */

Comment is still true and no more or less obvious than it was with the old code
I think so I don't really see why it should be removed with this change.

Doesn't the prefix "aligned" make this comment somehow redundant?

quoted

 	struct {
 		u32 accel_val[3];
-		s64 timestamp __aligned(8);
+		aligned_s64 timestamp;
 	} scan;

...

quoted

-		s32 sampled_vals[4] __aligned(16);
+		s32 sampled_vals[4];

Hmm. I can't immediately recall why that aligned(16) is therebut
it's not related to the rest of this change so I'm not sure we should touch
it. I don't think we ever required quaternions to be aligned as a whole so
this does feel odd but in the category of something we should be careful
touching or at very least do it in a different patch where it stands out.

I have checked the code and find nothing that justifies this, I can split it
to a separate patch, though.

Note, among ISH HID drivers it's the only one with a such...

quoted

+		aligned_s64 timestamp;
 	} scan;

-- 
With Best Regards,
Andy Shevchenko