On 12/11/2024 6:43 AM, Bjorn Andersson wrote: > On Tue, Dec 10, 2024 at 02:22:27AM +0530, Akhil P Oommen wrote: >> On 12/10/2024 1:24 AM, Rob Clark wrote: >>> On Mon, Dec 9, 2024 at 12:20 AM Akhil P Oommen <quic_akhilpo@xxxxxxxxxxx> wrote: >>>> >>>> When kernel is booted in EL2, SECVID registers are accessible to the >>>> KMD. So we can use that to switch GPU's secure mode to avoid dependency >>>> on Zap firmware. Also, we can't load a secure firmware without a >>>> hypervisor that supports it. >>> >>> Shouldn't we do this based on whether zap node is in dtb (and not disabled)? >> >> This is better, isn't it? Otherwise, multiple overlays should be >> maintained for each soc/board since EL2 can be toggled from bootloader. >> And this feature is likely going to be more widely available. >> > > The DeviceTree passed to the OS needs to describe the world that said OS > is going to operate in. If you change the world you need to change the > description. > There are several other examples where this would be necessary > (remoteproc and watchdog to name two examples from the Qualcomm upstream > world). But basic things work without those changes, right? For eg: Desktop UI > > So, if we can cover this by zap-shader being enabled or disabled, that > sounds like a clean and scaleable solution. I think we are focusing too much on zap shader. If the driver can determine itself about access to its register, shouldn't it be allowed to use that? -Akhil > > Regards, > Bjorn
