Created attachment 16017 [details] Xorg log with prints of LVDS and PIXCLK reads & writes PowerMac4,3 White iBook G3 800MHz 32MB VRAM with Radeon Mobility 7500. Xorg logs which print out LVDS and PIXCLK info here: http://bigw.org/~dan/x-debug.log I've narrowed down the issue to legacy_output.c, RADEONEnableDisplay(), around line 865 where it does: 862 tmp |= RADEON_LVDS_DISPLAY_DIS; 863 tmp &= ~(RADEON_LVDS_ON | RADEON_LVDS_BLON | RADEON_LVDS_EN); 864 ErrorF("%s (#%d): WRITE 0x%lX -> RADEON_LVDS_GEN_CNTL\n", __func__, __LINE__, tmp); 865 OUTREG(RADEON_LVDS_GEN_CNTL, tmp); the problem write is 0x52622 -> LVDS_GEN_CNTRL. At this point the panel bloom starts. Switching VTs after X has started also corrupts the font (looks like every other vertical pixel column is not displayed or something), not sure if that's related at all.
Actual backtrace at this point is: (gdb) bt #0 RADEONEnableDisplay (output=<value optimized out>, bEnable=<value optimized out>) at /usr/include/xorg/compiler.h:1232 #1 0x0e82da38 in radeon_dpms (output=<value optimized out>, mode=3) at radeon_output.c:433 #2 0x0e82a074 in RADEONBlank (pScrn=<value optimized out>) at radeon_crtc.c:703 #3 0x0e812350 in RADEONScreenInit (scrnIndex=0, pScreen=0x102677b0, argc=<value optimized out>, argv=<value optimized out>) at radeon_driver.c:3067 #4 0x10021990 in AddScreen () #5 0x1006593c in InitOutput () #6 0x10022178 in main () (gdb) where the line in RADEONEnableDisplay() that is causing the issue is the line #865 as described in my previous comment.
Closing as I don't have the hardware anymore and even if I did nobody really makes up-to-date PPC distros either.
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