Coverity: nvkm_dp_train(): Integer handling issues

coverity-bot
2022-11-10T16:50:45Z

Hello!

This is an experimental semi-automated report about issues detected by
Coverity from a scan of next-20221110 as part of the linux-next scan project:
https://scan.coverity.com/projects/linux-next-weekly-scan

You're getting this email because you were associated with the identified
lines of code (noted below) that were touched by commits:

Wed Nov 9 10:43:10 2022 +1000
8bb30c882334 ("drm/nouveau/disp: add method to trigger DP link retrain")

Coverity reported the following:

*** CID 1527267: Integer handling issues (NEGATIVE_RETURNS)
drivers/gpu/drm/nouveau/nvkm/engine/disp/dp.c:458 in nvkm_dp_train()
452 u8 pwr;
453
454 /* Retraining link? Skip source configuration, it can mess up the active modeset. */
455 if (atomic_read(&outp->dp.lt.done)) {
456 for (rate = 0; rate < outp->dp.rates; rate++) {
457 if (outp->dp.rate[rate].rate == ior->dp.bw * 27000)
vvv CID 1527267: Integer handling issues (NEGATIVE_RETURNS)
vvv "ret" is passed to a parameter that cannot be negative.
458 return nvkm_dp_train_link(outp, ret);
459 }
460 WARN_ON(1);
461 return -EINVAL;
462 }
463

If this is a false positive, please let us know so we can mark it as
such, or teach the Coverity rules to be smarter. If not, please make
sure fixes get into linux-next. :) For patches fixing this, please
include these lines (but double-check the "Fixes" first):

Reported-by: coverity-bot <keescook+coverity-bot@chromium.org>
Addresses-Coverity-ID: 1527267 ("Integer handling issues")
Fixes: 8bb30c882334 ("drm/nouveau/disp: add method to trigger DP link retrain")

Thanks for your attention!

--
Coverity-bot