[igt-dev] [PATCH i-g-t] lib/igt_kms: only check chamelium's presence in chamelium tests

[Martin Peres]

On 22/03/2021 09:29, Kunal Joshi wrote:
> On 2021-03-22 at 08:29:02 +0200, Martin Peres wrote:
>> On 22/03/2021 07:26, Kunal Joshi wrote:
>>> Avoid checking if chamelium is present or not in non chamelium
>>> tests as its just an overhead.
>>
>> The point of doing this was to stop having screens in CI and instead mostly
>> have chameliums. This means that we need to make sure the chamelium exposes
>> all the ports before starting a KMS test, since some tests may have left the
>> screens disconnected.
>>
>> Is that making sense?
> 
> Thanks martin for having a look and yeah i got your point,
> 
> But for checking all the ports are connected we can have a script which
> checks it before the execution starts rather than checking it everytime

Yeah, but then that would not protect against tests that would forget to 
re-plug the screens and thus would lead to unstable IGT results when the 
test list is randomized (shard runs).

I think the idea was that the overhead of checking was measured in ms on 
devices that have a chamelium, and no impact at all on machines without 
a chamelium, so the convenience was deemed greater than the cost.

Do you have specific measurements that would contradict this?

> 
> Currently when chamelium is not reachable we get SIGQUIT on all the
> tests
> 
> Starting subtest: basic-fence-flip
> Received signal SIGQUIT.
> Stack trace:
> #0 [fatal_sig_handler+0xd6]
> #1 [killpg+0x40]
> #2 [pselect+0x59]
> #3 [xmlrpc_server_info_disallow_auth_ntlm+0x389]
> #4 [xmlrpc_server_info_disallow_auth_ntlm+0x786]
> #5 [xmlrpc_server_info_disallow_auth_ntlm+0xd1f]
> #6 [xmlrpc_client_call2+0xa8]
> #7 [xmlrpc_client_call2f_va+0x9e]
> #8 [__chamelium_rpc_va+0x87]
> #9 [__chamelium_rpc.constprop.8+0x8c]
> #10 [chamelium_wait_reachable+0x65]
> #11 [igt_display_require+0xbe]
> #12 [test_flip+0x4b]
> #13 [__real_main1093+0x1c38]
> #14 [main+0x27]
> #15 [__libc_start_main+0xe7]
> #16 [_start+0x2a]
> 
> When chamelium is not reachable chamelium_wait_reachable() never returns
> back and we have inactivity timeout which kills the test.

Isn't that exactly what we want? This seems to be a setup error, and we 
get a clear message: we can't check the state of the chamelium, so 
better not run KMS tests which depend on a state we can't check.

> 
> Regards
> Kunal Joshi
>