[Openpvrsgx-devgroup] Building the 1.7.862890 branch for x86

[H. Nikolaus Schaller]

Hi Julius,

> Am 31.05.2024 um 21:29 schrieb Julius Schwartzenberg <julius.vrijheid at freedom.nl>:
> 
> On 30.05.24 22:57, Julius Schwartzenberg wrote:
>> On 30.05.24 15:25, H. Nikolaus Schaller wrote:
>>> So please try letux-6.8-rc4. I have tested and can compile it for x86 with letux_defconfig.
>>> 
>>> MBP1320Nikolaus:master hns$ ls -l ./drivers/gpu/drm/pvrsgx/1.17.4948957/eurasia_km/*.mod
>>> -rw-r--r--  1 hns  staff  3805 30 Mai 15:40 ./drivers/gpu/drm/pvrsgx/1.17.4948957/eurasia_km/pvrsrvkm_gma3600_sgx545_10141.mod
>>> -rw-r--r--  1 hns  staff  3789 30 Mai 15:41 ./drivers/gpu/drm/pvrsgx/1.17.4948957/eurasia_km/pvrsrvkm_gma500_sgx535_126.mod
>>> MBP1320Nikolaus:master hns$
>> Ah this seems interesting! I should be able to load up pvrsrvkm_gma3600_sgx545 on my hardware? How should I set CONFIG_DRM_GMA500?
> 
> I compiled and loaded this branch with the module, but nothing shows up apart from pvrsrvkm_gma3600_sgx545 being listed in the `lsmod` output. Nothing in `dmesg` and nothing in /proc.

Ok, nothing in dmesg is a good sign :)

But there should be a /proc/pvr...

Most likely the driver is loaded as module, but not probed. This is something where I have the least experience with on x86 systems because they are special compared to typical embedded or mobile SoC (ARM/MIPS).

On all systems I play with, there is a device tree file which defines setting up clocks and references to the sgx driver and is providing the base address of the sgx interface registers is done. This makes the boot process not only load the module but also probe it and  configure it for special hardware setups.

What I don't know is how this works on x86 devices. Wikipedia says: https://en.wikipedia.org/wiki/Devicetree#:~:text=Personal%20computers%20with%20the%20x86,e.g.%20ACPI)%20to%20discover%20hardware.

This could mean that we likely have to add something to the driver and the driver should know what would be defined in the device tree. 
Maybe it is what we found in the psb directory for the 1.7 kernel driver? And which should be included in an x86 build?

> 
> I will probably not be able to test the coming months, but hope to still finish getting the other branch compiled and then start testing again in a few months.

No problem... SGX is out there for almost 20 years now (SGX520/530 released Jul 2005 according to Wikipedia) so that a few months don't make a significant difference :)

And I won't have too much spare time either. Just refreshing the branches every week to follow upstream (changes).

Best regards,
Nikolaus