Re: [PATCH] APEI/ERST: Fix error message formatting

From: Naveen N. Rao
Date: Thu Aug 01 2013 - 06:11:03 EST

On 07/31/2013 11:30 PM, Bjorn Helgaas wrote:
On Wed, Jul 31, 2013 at 3:46 AM, Naveen N. Rao
<naveen.n.rao@xxxxxxxxxxxxxxxxxx> wrote:

My key question was about why we are using a field width of 10 implying a
32-bit value, rather than a field width of 18 as suggested by the data type?
This shouldn't truncate the value, but if we are specifying the field width
for alignment, seems to me it is better to match the data type.

%pR uses a field width of 10 (two for "0x", eight for the value)
simply because the majority of resource values fit in 32 bits. Larger
values extend the width, so it's not a question of truncating any
data. But it's no fun to read memory addresses when most of them have
eight extra leading zeros (the high 32-bits of a 64-bit value). I
think the same applies here; most ACPI table addresses still fit in 32

We *do* use a field width of 18 for the e820 table, even though many
of those regions fit in 32 bits. But that's sort of an exception
because it's a table where addresses above 4GB are pretty common.

Makes sense, thanks for the explanation.

But at the end of the day, I guess I'm just stating my personal
preferences and yours might be different.

Right - I'd probably prefer just %#llx. But yeah, the currently used field width of 10 looks fine too.


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