Quoting Yao, Jia (2026-09-21 20:33:03) > Hi @Lahtinen, Joonas, > > The key is LSC_CHICKEN_BIT_0 is a global register. > > Even we use per-client, we should consider the following cases: > > 1. Should conflicting configurations within a client be rejected? > I recommend the first setting should be latched.
>From uAPI perspective it would be simpler to set this at the DRM client level at once. However we don't seem to have such uAPI in active use currently (all drm_noop) so you'd have to compare the complexity between indirectly setting it at DRM client level by first created context or adding such an uAPI to set it explicitly per client. > 2. Should conflicting configurations across different clients be rejected? > I think the latter setting can cover previous one. DRM clients need to be indepenent from the driver perspective, we can't do that. The whole point of making it per DRM client is that given the impacted SKU only has 1 CCS engine. We have the address space matching requirement between CCS and RCS, so when both CCS and RCS are running, we know they belong to the same DRM client and thus they will not conflict with the WA mode. And if only one of them is running, there can be no conflict either as it's just one context. > Even like this, still can't cover all the race condition. Which race conditions do you think would remain? We definitely have to eliminate any race conditions to land this. Regards, Joonas
