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Re: [PATCH v2 5/5] spi: s3c64xx: use unsigned type for fifo handling variables

From Andi Shyti <andi@etezian.org>
Newsgroups linux.kernel
Subject Re: [PATCH v2 5/5] spi: s3c64xx: use unsigned type for fifo handling variables
Date 2016-07-05 17:10 +0200
Message-ID <rRA93-4vb-11@gated-at.bofh.it> (permalink)
References <rORg5-IJ-11@gated-at.bofh.it> <rORg6-IJ-31@gated-at.bofh.it> <rRzZn-4bX-11@gated-at.bofh.it>
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Hi Mark,

> > The 'quirks' variable cannot ever be negative, therefore use u8
> > instead of int. The 8 bit size is given from the fact that
> > currently the quirks variable has very few statuses.
> > 
> > The rx_lvl_offset and tx_st_done store shift values, so that u8
> > is a proper size.
> > 
> > fifo_lvl_mask stores a series of masks, to be in we will keep the
> > 32 bit size.
> 
> What's the advantage of these changes?  This feels like microptimisation
> of something that shouldn't be a big performance issue and it's not
> always the case that the compiler does something more sensible with
> smaller or unsigned types.  I'm not saying don't do it, I'm just saying
> that it's not clear to me what the win is.

not much indeed. Just something that was a little bothering me
while I was reading through.

Please, feel free to drop it.

Thanks,
Andi

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Thread

[PATCH v2 0/5] s3c64xx: consider the case of a disconnected CS line  and some code rework Andi Shyti <andi.shyti@samsung.com> - 2016-06-28 04:50 +0200
  [PATCH v2 3/5] spi: s3c64xx: do not configure the device twice Andi Shyti <andi.shyti@samsung.com> - 2016-06-28 04:50 +0200
  [PATCH v2 5/5] spi: s3c64xx: use unsigned type for fifo handling  variables Andi Shyti <andi.shyti@samsung.com> - 2016-06-28 04:50 +0200
    Re: [PATCH v2 5/5] spi: s3c64xx: use unsigned type for fifo handling  variables Mark Brown <broonie@kernel.org> - 2016-07-05 17:00 +0200
      Re: [PATCH v2 5/5] spi: s3c64xx: use unsigned type for fifo handling  variables Andi Shyti <andi@etezian.org> - 2016-07-05 17:10 +0200

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