Re: [PATCH] iio: Fix the sorting functionality in iio_gts_build_avail_time_table

[Matti Vaittinen <mazziesaccount@gmail.com>]

On 3/23/24 20:13, Jonathan Cameron wrote:
> On Wed, 20 Mar 2024 09:02:46 +0200
> Matti Vaittinen <mazziesaccount@gmail.com> wrote:
> 
>> Hi Jonathan, all.
>>
>> I am resending this as I don't think I found the mail from lore. I wrote
>> this using my phone so maybe it was sent as HTML and stuck to some
>> filters. If you receive this twice - I am sorry...
>>
>> la 16. maalisk. 2024 klo 15.40 Jonathan Cameron <jic23@kernel.org
>> <mailto:jic23@kernel.org>> kirjoitti:
>>
>>   > On Fri, 15 Mar 2024 15:49:10 -0500
>>   > Chenyuan Yang <chenyuan0y@gmail.com <mailto:chenyuan0y@gmail.com>>
>>   > wrote:
>>   >
>>   > > Hi Matti,
>>   > >
>>   > > Thanks for your reply!
>>   > >
>>   > > > I think the suggested-by tag is a bit of an overkill :) I don't feel
>>   > > > like taking the credit - you spotted the problem and fixed it!
>>   > >
>>   > > You did help me figure out the real issue here and how to fix it :)
>>   > >
>>   > > > Do you think you could fix the removal of the duplicates too?
>>   > >
>>   > > Sure, I can help to implement the deduplication logic.
>>   > > Here is a potential patch for it based on your help.
>>   > > Besides, I changed the stop condition in the inner loop to `j < idx`
>>   > > since the current last index should be `idx - 1`.
>>   >
>>   > Matti, I didn't follow why duplicates are a problem?
>>
>> The function here builds the tables for available integration times.
>> These are shown to users via sysfs (if I'm not mistaken) - and while the
>> user-space algorithms may tolerate dublicates, they are ugly (in my
>> opinon) when available times are manually listed.
>>
>>
>>   > Sure the code is less efficient, but do we end up with a wrong
>>   > answer as a result (I've not checked logic, but I'd expect either
>>   > first or last of repeating values to be used depending on the alg).
>>
>> If we discuss completely omitting duplicated times from the driver
>> (which was one thing I referred in my previous mail) - then we are
>> likely to face problems as there can be register values, which then
>> can't be translated to times, read from a HW.
>>
>> Eg, we need to have everything described in driver tables used for
>> driver's computations - but (in my opinion) we should drop duplicates
>> from these tables which we hand over via sysfs.
>>
> All makes sense. Thanks for the explanation.

Hi Chenyuan

I don't think I have seen a patch fixing this merged? Do you know if I 
have just missed it? If not, do you still plan to send a fix to this or 
should I do it?

Yours,
	-- Matti

-- 
Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland

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