On Fri, Jul 02, 2021 at 01:33:50PM +0100, Tvrtko Ursulin wrote:
On 01/07/2021 21:23, Matt Roper wrote:
From: Lucas De Marchi lucas.demarchi@intel.com
Besides the arch version returned by GRAPHICS_VER(), new platforms contain a "release id" to make clear the difference from one platform to another. Although for the first ones we may use them as if they were a
What does "first ones" refer to here?
XeHP-SDV and DG2. The additional register that commit 01eb15c9165e ("drm/i915: Add DISPLAY_VER() and related macros") talks about is not available for these platforms. Here we hardcode them in software to something that makes sense and it allows the driver to be properly prepared for future platforms.
major/minor version, that is not true for all platforms: we may have a `release_id == n` that is closer to `n - 2` than to `n - 1`.
Hm this is a bit confusing. Is the sentence simply trying to say that, as the release id number is growing, hw capabilities are not simply accumulating but can be removed as well? Otherwise I am not sure how the user of these macros is supposed to act on this sentence.
this is explaining why those numbers can't be interpreted as major/minor and hence why here it's called "release" rather than "minor".
Your interpretation is correct, except that a feature not being there doesn't necessarily mean it got removed at some point. I might just had never been in that particular release: i.e. GRAPHICS_VER_FULL() == 14.5 doesn't necessarily mean it comes after 14.3, with additional features/fixes.
Lucas De Marchi