On 5/8/25 8:33 PM, Connor Abbott wrote: > On Thu, May 8, 2025 at 2:14 PM Konrad Dybcio <konradyb...@kernel.org> wrote: >> >> From: Konrad Dybcio <konrad.dyb...@oss.qualcomm.com> >> >> SC8180X (A680) and SA8775P (A663) require a write to that register, >> while other SKUs are fine with the default value. Don't overwrite it >> needlessly, requiring the developer to read the value back from >> hardware just to put it in the driver again, introducing much more room >> for error. > > I'm not sure I understand that last sentence. The original reason I > always wrote it was that for host image copy we need to know the value > of macrotile_mode, so again the value exposed to userspace must match > what's set in the HW. We can't read the value from the HW and send it > to userspace, because userspace queries this when creating the > physical device during device enumeration and we really don't want to > spuriously turn on the device then. That means the safest thing is to > always program it, guaranteeing that it always matches. Otherwise we > just have to hope that the default value matches what we expect it to > be. > > I know you're copying this from kgsl, but kgsl doesn't expose the > macrotile_mode to userspace. I expect that HIC was added afterwards > and only works via hacks there (if it's even supported at all on the > relevant SoCs).
Alright, I think I'll include it in the common UBWC config (even though it only concerns the GPU), as IIUC it may differ between platforms implementing the same GPU SKU Konrad
