3.9.12. SGX Debug Info¶
The TI OMAP/AM/DM SGX Graphics Driver is closely tied to the environment it is running under, and the configuration it is built with. This article mentions debugging methods specific to Linux.
Baselining the current SGX driver environment
The current SGX driver environment on the target can be observed using the below script.
This script performs the below actions:
#!/bin/sh echo "WSEGL settings" cat /etc/powervr.ini echo "------" echo "ARM CPU information" cat /proc/cpuinfo echo "------" echo "SGX driver information" cat /proc/pvr/version echo "------" echo "Framebuffer settings" fbset -i echo "------" echo "Rotation settings" cat /sys/class/graphics/fb0/rotate echo "------" echo "Kernel Module information" lsmod echo "------" echo "Boot settings" cat /proc/cmdline echo "------" echo "Linux Kernel version" uname -a
Run-time checks/configuration of the SGX driver
One can confirm whether the SGX drivers have been properly installed by checking the following
- One should have seen the message on serial console- “Initializing the graphics driver ...” just before getting the linux command prompt.
- lsmod shows pvrsrvkm module inserted successfully without any error messages on console.
The SGX driver can be configured at run-time on the target using a configuration file.
The optional configuration file is installed by the Processor SDK installer at,
Configuration items are specified using the below syntax
Important configuration parameters are mentioned below.
* WindowSystem - This configuration item controls the low level window system that the EGL implementation should hook it up. This item takes the below values * libpvrDRMWSEGL.so (DRM-based WS for VSync synchronised writes to Framebuffer - slower, but avoids tearing) * libpvrGBMWSEGL.so (GBM-based WS where it is up to application to perform KMS operations)
* DisableHWTextureUpload - This configuration item enables/disables the use of SGX Transfer queue hardware. * If set to 1, uses software upload (copying from driver to SGX) of textures, rather than transfer queue (using the SGX hardware). * Useful to rule out problems in TQ.
* DefaultPixelFormat - This configuration item sets the default display pixel format.
- For eg if one wants to configure the default pixel format, then edit /etc/powervr.ini to have following line
- For AM3 Beagle Bone Black EVM
SGX Driver Failure Modes (Installation)
Unable to install the kernel modules (pvrsrvkm.ko)
1. The Linux kernel has to be built with “modules” support (make ti-sgx-ddk-km and make ti-sgx-ddk-km_install)
2. The kernel modules of the Graphics driver have to be built, after the linux kernel is built in the above manner. ie, the kernel modules need to match the kernel version that will actually run on the target.
3. If the services kernel module (pvrsrvkm.ko) does not load, it is likely because of mismatches between user mode binaries and kernel modules. If the kernel modules are built correctly as specified, post the issue on the E2E forum with the output of the gfx_check.sh script linked in earlier section.
SGX Driver Failure Modes (Run time)
Vertical Tearing/ Artifacts/ Clipping issues/ Missing objects
This could potentially be due to an incorrect usage in the OpenGL application, or point to an issue in the driver. Note that the deferred rendering mode of the SGX HW, will cause different behaviour compared to the immediate renderers found on desktops.
Please contact TI through the Linux E2E forums (https://e2e.ti.com/)
Demos are not running at required speed, How to check SGX clock rate?
If the demos are running slower than expected, check and ensure that the clock frequency set for the SGX driver is correct. This can be done by the following code in the KM kernel drivers -
File - eurasia_km/services4/system/omap/sysutils_linux.c Function - EnableSGXClocks()
You can print the SGX clock rate in debug build as below -
IMG_UINT32 rate = clk_get_rate(psSysSpecData->psSGX_FCK); PVR_TRACE(("Sgx clock is %dMHz", HZ_TO_MHZ(rate)));
Depending on the TI platform used, this will vary from 200 to 532 MHz. Ensure that SGX is running at the right clock.
If this is right & still demos are not running with expected performance, it is needed to optimize the application, and its usage of OpenGL API.
Qt demos do not work when powerVR is enabled
1. Confirm that the GLES2 demos provided in the Graphics SDK are running properly with default SDK configuration of the window system.
- Confirm that kernel module (pvrsrvkm.ko) is successfully loaded.
3. Confirm with fbset command to check alpha to be non zero. If not set to appropriate value using fbset. QT supports 16, 32 bpp but expects alpha to be non zero for 32 bpp.
4. If above steps are correct, post to E2E forum with the output of the gfx_check.sh script linked in earlier section. Also attach the console log, with the below option enabled in the environment
Posting to E2E forum
For suggestions or recommendations or bug reports, post details of your application as below to the E2E forums (https://e2e.ti.com/), with below information:
- Output of gfx environment baseline script available below, run on the target:
- Details of UI application, as shown in below sheet.
These two outputs will help in debugging common issues.