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driverembedded-linuxxorg

Xorg crashing in custom image

I generated an image to an advantech PCM-9375 board using the yocto system (branch dunfell).

The outcome uses Xorg as the video manager, however, the application is crashing due to the geode driver installed with it.

I debugged it and discovered that the crashes happen when the driver function LXReadMSR is called with the parameters: addr=0x80002000h, lo=0xbffff994 and hi=0xbffff998. The last two are pointers, and their contents are: 5136 and 0, respectively. The snippet below is the gdb's backtrace:

(gdb) bt
#0  0xb7693ba7 in LXReadMSR (hi=0xbffff998, lo=0xbffff994, addr=2147491840) at ../../xf86-video-geode-2.11.20/src/lx_driver.c:131
#1  LXReadMSR (addr=2147491840, lo=0xbffff994, hi=0xbffff998) at ../../xf86-video-geode-2.11.20/src/lx_driver.c:126
#2  0xb7681eef in msr_create_geodelink_table (gliu_nodes=0xb76b2880 <gliu_nodes>) at ../../xf86-video-geode-2.11.20/src/cim/cim_msr.c:199
#3  0xb7682400 in msr_init_table () at ../../xf86-video-geode-2.11.20/src/cim/cim_msr.c:82
#4  0xb7693282 in LXPreInit (pScrni=0x6a79e0, flags=0) at ../../xf86-video-geode-2.11.20/src/lx_driver.c:349
#5  0x00480986 in InitOutput (pScreenInfo=0x688280 <screenInfo>, argc=12, argv=0xbffffc44) at ../../../../xorg-server-1.20.14/hw/xfree86/common/xf86Init.c:522
#6  0x00444525 in dix_main (argc=12, argv=0xbffffc44, envp=0xbffffc78) at ../../xorg-server-1.20.14/dix/main.c:193
#7  0x0042d89b in main (argc=12, argv=0xbffffc44, envp=0xbffffc78) at ../../xorg-server-1.20.14/dix/stubmain.c:34

Looking in the documentation of the processor, I found out that addr points to GLD_MSR_CAP register (chapter "6.6.1.1 GLD Capabilities MSR (GLD_MSR_CAP)" in the documentation), however I didn't figure out what's happening.

Solutions tried:

  • Insertion of the CLI kernel instruction "iomem=relaxed", as pointed by item 6 of the driver's readme file in its github repository;
  • Replacing of the kernel configuration "CONFIG_BLK_DEV_CS5535=y" by "CONFIG_BLK_DEV_CS5536=y".

None of them worked.

Xorg version: 1.20.14

Geode driver version: 2.11.20

Did anyone have a similar problem? Does anyone know what's happenning?

My next tries will be the modification of kernel config parameters, but there are a lot and I'don't know which of them are related to the problem.

Solution

  • Problem solved when the kernel option "CONFIG_X86_IOPL_IOPERM" was enabled.

    I've come to this solution after reading this post.