[Openpvrsgx-devgroup] trying to get SGX 1.14 running on DM3730 (SGX530)

H. Nikolaus Schaller hns at goldelico.com
Thu Nov 21 15:40:44 CET 2019

> Am 21.11.2019 um 14:28 schrieb H. Nikolaus Schaller <hns at goldelico.com>:
> Hi Adam,
>> Am 21.11.2019 um 14:15 schrieb Adam Ford <aford173 at gmail.com>:
>> On Thu, Nov 21, 2019 at 5:58 AM H. Nikolaus Schaller <hns at goldelico.com> wrote:
>> Above it closed card0 and started to open card1 indicating to me it
>> didnt' find what it wanted.  Do you know what it wanted?
> Not yet... This is what I try to find out next by adding printf to libdrm.

Ok, I have new information. But no solution yet :(

drmGetVersion() returns exactly what was passed by the kernel. So there is
no bug in the ioctl() interface or our kernel module.

drmGetVersion(fd=3) is called twice by PVRDRMOpenRender from libsrv_um.so.1

and then called twice (fd=4) from PVRDRMOpenDisplay

So the logic to scan through /dev/dri/card* for DRM_VERSION and the rules what
it is looking for are hidden inside libsrv_um.so and most likely in the
PVRDRMOpenDisplay function :(

And even the open() system call for the second run. The first two seem to be
drmOpenMinor("/dev/dri/renderD128") and drmOpenMinor("/dev/dri/renderD129");

So at the moment I can only speculate that there is some code in libsrv_um.so
which dynamically makes the search pattern different between running on am335x
and dm3730.

Well, we have something similar for the dra7/jacinto6/omap5432 case and have
to patch the binary libsrv_um.so.1.14.3699939.

But there the unpatched system explicitly says that it does not support the
OMAP5432 unless we patch it (likely by reading out the machine DT property).

Here the am335x version running on dm3730 simply fails to find displays.


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