Hey all, so....I have an oldish iMac 24 inch. It comes with a Radeon Mobility HD 4850. After install of Stretch testing, this worked fine, save for one small issue of the backlight not going out. As I run this as kind of a server with no need to see the screen most of the time, I'd like to get the backlight to go out. So I installed firmware-linux-nonfree. This actually causes me to get a blank screen...just the backlight on. I can ssh into the machine, but I get no screen at all (http://askubun tu.com/questions/688388/14-04-gets-black-screen-unless-radeon-modeset-0 ). I DO however see the backlight go out. Right now I'm using radeon.modeset=0 to get an active screen again. My question is there any way I can troubleshoot getting the backlight to go out? I've got to:
https://wiki.debian.org/ATIProprietary https://wiki.archlinux.org/index.php/ATI But I'm just not having much success. Thanks for any assistance you can give....info below. lspci and dmesg:##SELECTION_END## 02:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] RV770/M98L [Mobility Radeon HD 4850] [ 10.356922] [drm:radeon_init [radeon]] *ERROR* No UMS support in radeon module! dmesg without the modeset: [ 10.914802] radeon 0000:02:00.0: VRAM: 512M 0x0000000000000000 - 0x000000001FFFFFFF (512M used) [ 10.914804] radeon 0000:02:00.0: GTT: 1024M 0x0000000020000000 - 0x000000005FFFFFFF [ 10.914806] [drm] Detected VRAM RAM=512M, BAR=256M [ 10.914807] [drm] RAM width 256bits DDR [ 10.914869] [TTM] Zone kernel: Available graphics memory: 4088066 kiB [ 10.914870] [TTM] Zone dma32: Available graphics memory: 2097152 kiB [ 10.914871] [TTM] Initializing pool allocator [ 10.914876] [TTM] Initializing DMA pool allocator [ 10.914895] [drm] radeon: 512M of VRAM memory ready [ 10.914896] [drm] radeon: 1024M of GTT memory ready. [ 10.914908] [drm] Loading RV770 Microcode [ 10.985259] radeon 0000:02:00.0: firmware: direct-loading firmware radeon/RV770_pfp.bin [ 11.015010] radeon 0000:02:00.0: firmware: direct-loading firmware radeon/RV770_me.bin [ 11.283904] radeon 0000:02:00.0: firmware: direct-loading firmware radeon/R700_rlc.bin [ 11.285010] radeon 0000:02:00.0: firmware: direct-loading firmware radeon/RV770_smc.bin [ 11.285019] [drm] External GPIO thermal controller with fan control [ 11.285034] [drm] radeon: power management initialized [ 11.437289] radeon 0000:02:00.0: firmware: direct-loading firmware radeon/RV770_uvd.bin [ 11.437338] [drm] GART: num cpu pages 262144, num gpu pages 262144 [ 11.438616] [drm] enabling PCIE gen 2 link speeds, disable with radeon.pcie_gen2=0 [ 11.441386] [drm] PCIE GART of 1024M enabled (table at 0x0000000000258000). [ 11.441422] radeon 0000:02:00.0: WB enabled [ 11.441425] radeon 0000:02:00.0: fence driver on ring 0 use gpu addr 0x0000000020000c00 and cpu addr 0xffff8800bdd54c00 [ 11.441427] radeon 0000:02:00.0: fence driver on ring 3 use gpu addr 0x0000000020000c0c and cpu addr 0xffff8800bdd54c0c [ 11.441903] radeon 0000:02:00.0: fence driver on ring 5 use gpu addr 0x0000000000056230 and cpu addr 0xffffc90001416230 [ 11.441905] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013). [ 11.441906] [drm] Driver supports precise vblank timestamp query. [ 11.441908] radeon 0000:02:00.0: radeon: MSI limited to 32-bit [ 11.441938] radeon 0000:02:00.0: radeon: using MSI. [ 11.441963] [drm] radeon: irq initialized. [ 11.488229] [drm] ring test on 0 succeeded in 1 usecs [ 11.488235] [drm] ring test on 3 succeeded in 2 usecs [ 11.662883] [drm] ring test on 5 succeeded in 1 usecs [ 11.662890] [drm] UVD initialized successfully. [ 11.663277] [drm] ib test on ring 0 succeeded in 0 usecs [ 11.663292] [drm] ib test on ring 3 succeeded in 0 usecs [ 12.312126] [drm] ib test on ring 5 succeeded [ 12.312699] [drm] radeon atom DIG backlight initialized [ 12.312702] [drm] Radeon Display Connectors [ 12.312703] [drm] Connector 0: [ 12.312704] [drm] DP-1 [ 12.312705] [drm] HPD2 [ 12.312706] [drm] DDC: 0x7e60 0x7e60 0x7e64 0x7e64 0x7e68 0x7e68 0x7e6c 0x7e6c [ 12.312707] [drm] Encoders: [ 12.312708] [drm] DFP1: INTERNAL_UNIPHY [ 12.312709] [drm] Connector 1: [ 12.312710] [drm] DP-2 [ 12.312711] [drm] HPD3 [ 12.312712] [drm] DDC: 0x7e20 0x7e20 0x7e24 0x7e24 0x7e28 0x7e28 0x7e2c 0x7e2c [ 12.312713] [drm] Encoders: [ 12.312714] [drm] DFP2: INTERNAL_UNIPHY [ 12.312715] [drm] Connector 2: [ 12.312716] [drm] LVDS-1 [ 12.312717] [drm] Encoders: [ 12.312718] [drm] LCD1: INTERNAL_KLDSCP_LVTMA [ 12.312719] [drm] Connector 3: [ 12.312719] [drm] VGA-1 [ 12.312721] [drm] DDC: 0x7e40 0x7e40 0x7e44 0x7e44 0x7e48 0x7e48 0x7e4c 0x7e4c [ 12.312722] [drm] Encoders: [ 12.312723] [drm] CRT1: INTERNAL_KLDSCP_DAC1 [ 13.005463] [drm] fb mappable at 0xC0459000 [ 13.005465] [drm] vram apper at 0xC0000000 [ 13.005466] [drm] size 5947392 [ 13.005467] [drm] fb depth is 24 [ 13.005468] [drm] pitch is 5632 [ 13.005547] fbcon: radeondrmfb (fb0) is primary device [ 13.086983] radeon 0000:02:00.0: fb0: radeondrmfb frame buffer device
