On Wed, Jul 28, 2021 at 01:36:56AM +0000, Wu, Hao wrote:
I'm not entirely sure. I seem to recall there being examples of sysfsOn 7/26/21 3:12 PM, Russ Weight wrote:This change limited the output format to uuid_t, but if any hardware doesn't
On 7/26/21 1:26 PM, trix@xxxxxxxxxx wrote:Yes, it will.
From: Tom Rix <trix@xxxxxxxxxx>I'm fowarding feedback from Tim Whisonant, one of the OPAE userspace
An fpga region's compat_id is exported by the sysfs
as a 128 bit hex string formed by concatenating two
64 bit values together.
The only user of compat_id is dfl. Its user library
opae converts this value into a uuid.
ex/
$ cat /sys/class/fpga_region/region1/compat_id
f3c9941350814aadbced07eb84a6d0bb
Is reported as
$ fpgainfo bmc
...
Pr Interface Id : f3c99413-5081-4aad-bced-07eb84a6d0bb
Storing a uuid as 2 64 bit values is vendor specific.
And concatenating them together is vendor specific.
It is better to store and print out as a vendor neutral uuid.
Change fpga_compat_id from a struct to a union.
Keep the old 64 bit values for dfl.
Sysfs output is now
f3c99413-5081-4aad-bced-07eb84a6d0bb
developers:
I think that this change to the sysfs for the compat_id node will
end up breaking the SDK, which does not expect the '-' characters to
be included when parsing the sysfs value. Currently, it is parsed as
a raw hex string without regard to any '-' characters. This goes for
any "guid" currently exported by sysfs and for what we read in the
device MMIO space.
And there are other places, like dfl-afu-main.c:afu_id_show()
outputs raw hex that sdk turns into a uuid.
Some options.
If no one but dfl will ever use it, then v1 of patchset.
If others can use it but don't want to change dfl, then v2 of patchset,
my favorite.
Or this one for uuid for everyone, what have been v3 but changed too much.
could dfl change generally to output uuid's to the sysfs ?
this would be generally helpful and a one time disruption to the sdk.
use uuid_t on hardware may have to convert it back from the sysfs output in
userspace. Leave it to print hardware values (e.g. from register), and convert
it in userspace should be fine too I think.
files returning different things for different drivers.
That being said it seems largely cosmetic to add the '-' in between.
If it breaks userspace, I'm against it. If you *need* it make a
compat_uuid entry or something in that case?
- Moritz