No backlight since linux-4.2.4 - drivers/gpu/drm/radeon/atombios_encoders.c

[Michael Burian]

On 10/27/15 03:36, Michel Dänzer wrote:
>>
>> [0] contains dmesg output with your patch applied (which fixes the backlight issue)
> 
> This is very surprising: The patch just adds some debugging output, it's
> not supposed to have any functional effect. Also, I don't see any of the
> debugging output added by the patch in
> dmesg-4.3.0-rc7-00003-g85051e2-dirty-2015-10-26-11-00-41-radeon-bl-debug.
>

> Are you sure that my patch was actually applied to the radeon driver
> when generating that file? Did you update the initrd with the patched
> radeon.ko?
> 

the build was done using "make -j4 deb-pkg" on a better equipped machine,
.deb packages were copied over and installed - maybe something interesting
happened

AFAICT the patch should have been applied, at least it was shown with
git diff and the -dirty suffix was added by the build system, not me.
All graphics related drivers are compiled in (=y) rather than as
modules (=m) in .config.

Another thing I tried yesterday was to add the old way right below the new one
(this fixes the backlight issue) enclosed by some debug statements that indicate
start / stop of the old / new method. (see atomdebug.diff - should be applied against
mainline)

-------------- next part --------------
radeon_start_backlight_new_way
>> execute D2AA (len 348, WS 4, PS 4)
   SET_ATI_PORT @ 0xD2B0
      port: 0 (MM)
   COMPARE_PS @ 0xD2B3
      src1: 
PS[0x00,0xFFFF8802]
.[7:0] -> 0x02
      src2: 
IMM 0x04
      result: NE LE
   JUMP_EQUAL @ 0xD2B7
      taken: no
      target: 0x0128
   COMPARE_PS @ 0xD2BA
      src1: 
PS[0x00,0xFFFF8802]
.[7:0] -> 0x02
      src2: 
IMM 0x05
      result: NE LE
   JUMP_EQUAL @ 0xD2BE
      taken: no
      target: 0x0113
   COMPARE_PS @ 0xD2C1
      src1: 
PS[0x00,0xFFFF8802]
.[7:0] -> 0x02
      src2: 
IMM 0x00
      result: NE GT
   JUMP_EQUAL @ 0xD2C5
      taken: no
      target: 0x00D8
   COMPARE_PS @ 0xD2C8
      src1: 
PS[0x00,0xFFFF8802]
.[7:0] -> 0x02
      src2: 
IMM 0x01
      result: NE GT
   JUMP_NOT_EQUAL @ 0xD2CC
      taken: yes
      target: 0x013D
   COMPARE_PS @ 0xD3E7
      src1: 
PS[0x00,0xFFFF8802]
.[7:0] -> 0x02
      src2: 
IMM 0x03
      result: NE LE
   JUMP_NOT_EQUAL @ 0xD3EB
      taken: yes
      target: 0x0151
   OR_REG @ 0xD3FB
      dst: 
REG[0x1EBC]
.[31:24] -> 0x00
      src: 
IMM 0x02
      dst: 
REG[0x1EBC]
.[31:24] <- 0x02
   AND_REG @ 0xD400
      dst: 
REG[0x1EBC]
.[31:24] -> 0x02
      src: 
IMM 0xFE
      dst: 
REG[0x1EBC]
.[31:24] <- 0x02
   EOT @ 0xD405
<<
radeon_stop_backlight_new_wayradeon_start_backlight_old_way
-------------- next part --------------
radeon_stop_backlight_new_wayradeon_start_backlight_old_way
>> execute D2AA (len 348, WS 4, PS 4)
   SET_ATI_PORT @ 0xD2B0
      port: 0 (MM)
   COMPARE_PS @ 0xD2B3
      src1: 
PS[0x00,0x0003]
.[7:0] -> 0x03
      src2: 
IMM 0x04
      result: NE LE
   JUMP_EQUAL @ 0xD2B7
      taken: no
      target: 0x0128
   COMPARE_PS @ 0xD2BA
      src1: 
PS[0x00,0x0003]
.[7:0] -> 0x03
      src2: 
IMM 0x05
      result: NE LE
   JUMP_EQUAL @ 0xD2BE
      taken: no
      target: 0x0113
   COMPARE_PS @ 0xD2C1
      src1: 
PS[0x00,0x0003]
.[7:0] -> 0x03
      src2: 
IMM 0x00
      result: NE GT
   JUMP_EQUAL @ 0xD2C5
      taken: no
      target: 0x00D8
   COMPARE_PS @ 0xD2C8
      src1: 
PS[0x00,0x0003]
.[7:0] -> 0x03
      src2: 
IMM 0x01
      result: NE GT
   JUMP_NOT_EQUAL @ 0xD2CC
      taken: yes
      target: 0x013D
   COMPARE_PS @ 0xD3E7
      src1: 
PS[0x00,0x0003]
.[7:0] -> 0x03
      src2: 
IMM 0x03
      result: EQ LE
   JUMP_NOT_EQUAL @ 0xD3EB
      taken: no
      target: 0x0151
   OR_REG @ 0xD3EE
      dst: 
REG[0x1EBC]
.[31:24] -> 0x02
      src: 
IMM 0x02
      dst: 
REG[0x1EBC]
.[31:24] <- 0x02
   OR_REG @ 0xD3F3
      dst: 
REG[0x1EBC]
.[31:24] -> 0x02
      src: 
IMM 0x01
      dst: 
REG[0x1EBC]
.[31:24] <- 0x03
   JUMP @ 0xD3F8
      target: 0x015B
   EOT @ 0xD405
<<
radeon_stop_backlight_old_way
-------------- next part --------------
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