On 2023-05-02 22:41:09, Joonas Lahtinen wrote: > Hi Jordan, > > This approach was specifically NACKed in the PAT index thread so please > at least mark any such series as RFC if they are intended to facilitate > further dialog on the topic. There was a preference expressed to not do anything from the i915 side, but I didn't know that my idea had been NACKed. > I've still not seen any explanation why this would be needed at this > specific case for the PAT index setting feature. Repeating here: You > should be able to detect missing extension by trying to use it. There's nothing specific to the set-pat extension, but I would've liked to use this query to detect I915_GEM_CREATE_EXT_SET_PAT. Therefore, I was hoping to show how simple implementation of such a query would be. It doesn't really seem like any further maintainence of the query would be required as new extensions are added. Additionally, I was hoping a similar approach could be adopted by Xe. It's not that anything is particularly difficult in the previous approach, but this seems like a pretty simple thing i915 could do to give userspace a clue about which extensions it knows about. -Jordan
