When my system boots and switches on KMS for my radeon graphics card, the screen goes blank and stays like that. I configured netconsole, and could capture this output with a null pointer dereference: [ 5.028256] device-mapper: uevent: version 1.0.3 [ 5.028454] device-mapper: ioctl: 4.27.0-ioctl (2013-10-30) initialised: dm-devel@redhat.com [ 5.161378] raid6: sse2x1 6263 MB/s [ 5.229408] raid6: sse2x2 9678 MB/s [ 5.297441] raid6: sse2x4 13655 MB/s [ 5.297492] raid6: using algorithm sse2x4 (13655 MB/s) [ 5.297543] raid6: using ssse3x2 recovery algorithm [ 5.297920] xor: automatically using best checksumming function: [ 5.337455] avx : 28637.000 MB/sec [ 5.339874] Btrfs loaded [ 5.404045] BTRFS: device fsid 5c6276a1-4ed4-440b-a88c-ef31ff30b9db devid 1 transid 18706 /dev/sdb2 [ 5.404504] BTRFS: device fsid 8810aab6-9344-48f4-ae25-828e60854b73 devid 1 transid 637 /dev/mapper/debian-root [ 5.406878] PM: Starting manual resume from disk [ 5.409361] BTRFS info (device dm-0): disk space caching is enabled [ 5.414950] BTRFS: detected SSD devices, enabling SSD mode [ 5.651353] systemd[1]: RTC configured in localtime, applying delta of 60 minutes to system time. [ 5.652742] systemd[1]: systemd 215 running in system mode. (+PAM +AUDIT +SELINUX +IMA +SYSVINIT +LIBCRYPTSETUP +GCRYPT +ACL +XZ -SECCOMP -APPARMOR) [ 5.653010] systemd[1]: Detected architecture 'x86-64'. [ 5.672246] systemd[1]: Inserted module 'autofs4' [ 5.672799] systemd[1]: Set hostname to <piranha>. [ 5.815370] systemd[1]: Starting Forward Password Requests to Wall Directory Watch. [ 5.815504] systemd[1]: Started Forward Password Requests to Wall Directory Watch. [ 5.815582] systemd[1]: Starting Remote File Systems (Pre). [ 5.816000] systemd[1]: Reached target Remote File Systems (Pre). [ 5.816084] systemd[1]: Starting Arbitrary Executable File Formats File System Automount Point. [ 5.816553] systemd[1]: Set up automount Arbitrary Executable File Formats File System Automount Point. [ 5.816636] systemd[1]: Starting Dispatch Password Requests to Console Directory Watch. [ 5.816731] systemd[1]: Started Dispatch Password Requests to Console Directory Watch. [ 5.816812] systemd[1]: Starting Paths. [ 5.817201] systemd[1]: Reached target Paths. [ 5.817266] systemd[1]: Expecting device dev-mapper-debian\x2dswap.device... [ 5.817558] systemd[1]: Expecting device dev-disk-by\x2duuid-fd7f3585\x2dbe5e\x2d432a\x2da6ad\x2d1ac043d62114.device... [ 5.817873] systemd[1]: Expecting device dev-mapper-debian\x2dhome.device... [ 5.818164] systemd[1]: Expecting device dev-disk-by\x2duuid-5c6276a1\x2d4ed4\x2d440b\x2da88c\x2def31ff30b9db.device... [ 5.818463] systemd[1]: Starting Root Slice. [ 5.827367] systemd[1]: Created slice Root Slice. [ 5.827437] systemd[1]: Starting User and Session Slice. [ 5.827964] systemd[1]: Created slice User and Session Slice. [ 5.828032] systemd[1]: Starting Delayed Shutdown Socket. [ 5.828441] systemd[1]: Listening on Delayed Shutdown Socket. [ 5.828507] systemd[1]: Starting /dev/initctl Compatibility Named Pipe. [ 5.828923] systemd[1]: Listening on /dev/initctl Compatibility Named Pipe. [ 5.828990] systemd[1]: Starting Journal Socket (/dev/log). [ 5.829398] systemd[1]: Listening on Journal Socket (/dev/log). [ 5.829465] systemd[1]: Starting Syslog Socket. [ 5.829881] systemd[1]: Listening on Syslog Socket. [ 5.829946] systemd[1]: Starting LVM2 metadata daemon socket. [ 5.830350] systemd[1]: Listening on LVM2 metadata daemon socket. [ 5.830416] systemd[1]: Starting Device-mapper event daemon FIFOs. [ 5.831182] systemd[1]: Listening on Device-mapper event daemon FIFOs. [ 5.831253] systemd[1]: Starting udev Control Socket. [ 5.831652] systemd[1]: Listening on udev Control Socket. [ 5.831720] systemd[1]: Starting udev Kernel Socket. [ 5.832114] systemd[1]: Listening on udev Kernel Socket. [ 5.832181] systemd[1]: Starting Journal Socket. [ 5.832585] systemd[1]: Listening on Journal Socket. [ 5.832658] systemd[1]: Starting System Slice. [ 5.833171] systemd[1]: Created slice System Slice. [ 5.833248] systemd[1]: Starting File System Check on Root Device... [ 5.833856] systemd[1]: Starting system-systemd\x2dfsck.slice. [ 5.834397] systemd[1]: Created slice system-systemd\x2dfsck.slice. [ 5.834472] systemd[1]: Starting system-getty.slice. [ 5.835017] systemd[1]: Created slice system-getty.slice. [ 5.835092] systemd[1]: Starting udev Coldplug all Devices... [ 5.836297] systemd[1]: Started Set Up Additional Binary Formats. [ 5.836373] systemd[1]: Mounting POSIX Message Queue File System... [ 5.840057] systemd[1]: Starting Load Kernel Modules... [ 5.840658] systemd[1]: Mounting Huge Pages File System... [ 5.841312] systemd[1]: Starting Create list of required static device nodes for the current kernel... [ 5.841963] systemd[1]: Mounting Debug File System... [ 5.842588] systemd[1]: Starting Journal Service... [ 5.843562] systemd[1]: Started Journal Service. [ 5.852431] fuse init (API version 7.23) [ 5.889130] random: nonblocking pool is initialized [ 5.891460] systemd-udevd[243]: starting version 215 [ 5.985453] BTRFS info (device dm-0): turning on discard [ 5.985513] BTRFS info (device dm-0): disk space caching is enabled [ 6.086904] EDAC MC: Ver: 3.0.0 [ 6.088056] EDAC ie31200: No ECC support [ 6.088401] ACPI Warning: SystemIO range 0x0000000000000428-0x000000000000042f conflicts with OpRegion 0x0000000000000400-0x000000000000047f (\PMIO) (20140724/utaddress-258) [ 6.088550] ACPI: If an ACPI driver is available for this device, you should use it instead of the native driver [ 6.088608] ACPI Warning: SystemIO range 0x0000000000000540-0x000000000000054f conflicts with OpRegion 0x0000000000000500-0x000000000000057f (\GPR2) (20140724/utaddress-258) [ 6.088757] ACPI Warning: SystemIO range 0x0000000000000540-0x000000000000054f conflicts with OpRegion 0x0000000000000500-0x0000000000000563 (\GPIO) (20140724/utaddress-258) [ 6.088911] ACPI: If an ACPI driver is available for this device, you should use it instead of the native driver [ 6.088966] ACPI Warning: SystemIO range 0x0000000000000530-0x000000000000053f conflicts with OpRegion 0x0000000000000500-0x000000000000057f (\GPR2) (20140724/utaddress-258) [ 6.089121] ACPI Warning: SystemIO range 0x0000000000000530-0x000000000000053f conflicts with OpRegion 0x0000000000000500-0x0000000000000563 (\GPIO) (20140724/utaddress-258) [ 6.089280] ACPI: If an ACPI driver is available for this device, you should use it instead of the native driver [ 6.089343] ACPI Warning: SystemIO range 0x0000000000000500-0x000000000000052f conflicts with OpRegion 0x0000000000000500-0x000000000000057f (\GPR2) (20140724/utaddress-258) [ 6.089495] ACPI Warning: SystemIO range 0x0000000000000500-0x000000000000052f conflicts with OpRegion 0x0000000000000500-0x0000000000000563 (\GPIO) (20140724/utaddress-258) [ 6.089642] ACPI: If an ACPI driver is available for this device, you should use it instead of the native driver [ 6.089700] lpc_ich: Resource conflict(s) found affecting gpio_ich [ 6.090471] input: Power Button as /devices/LNXSYSTM:00/LNXSYBUS:00/PNP0C0C:00/input/input2 [ 6.090563] ACPI: Power Button [PWRB] [ 6.093911] input: Power Button as /devices/LNXSYSTM:00/LNXPWRBN:00/input/input3 [ 6.093971] ACPI: Power Button [PWRF] [ 6.094583] ACPI: bus type USB registered [ 6.094655] usbcore: registered new interface driver usbfs [ 6.094713] usbcore: registered new interface driver hub [ 6.094791] usbcore: registered new device driver usb [ 6.098614] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver [ 6.099087] ehci-pci: EHCI PCI platform driver [ 6.099513] xhci_hcd 0000:00:14.0: xHCI Host Controller [ 6.099569] xhci_hcd 0000:00:14.0: new USB bus registered, assigned bus number 1 [ 6.100020] usb usb1: New USB device found, idVendor=1d6b, idProduct=0002 [ 6.100089] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1 [ 6.100147] usb usb1: Product: xHCI Host Controller [ 6.100212] usb usb1: Manufacturer: Linux 3.17.2.1 xhci_hcd [ 6.100267] usb usb1: SerialNumber: 0000:00:14.0 [ 6.100888] hub 1-0:1.0: USB hub found [ 6.100953] hub 1-0:1.0: 4 ports detected [ 6.101429] xhci_hcd 0000:00:14.0: xHCI Host Controller [ 6.101488] xhci_hcd 0000:00:14.0: new USB bus registered, assigned bus number 2 [ 6.101593] usb usb2: New USB device found, idVendor=1d6b, idProduct=0003 [ 6.101653] usb usb2: New USB device strings: Mfr=3, Product=2, SerialNumber=1 [ 6.101714] usb usb2: Product: xHCI Host Controller [ 6.101768] usb usb2: Manufacturer: Linux 3.17.2.1 xhci_hcd [ 6.101835] usb usb2: SerialNumber: 0000:00:14.0 [ 6.101964] hub 2-0:1.0: USB hub found [ 6.102022] hub 2-0:1.0: 4 ports detected [ 6.102386] ehci-pci 0000:00:1a.0: EHCI Host Controller [ 6.102437] ehci-pci 0000:00:1a.0: new USB bus registered, assigned bus number 3 [ 6.102500] ehci-pci 0000:00:1a.0: debug port 2 [ 6.105481] [drm] Initialized drm 1.1.0 20060810 [ 6.106457] ehci-pci 0000:00:1a.0: irq 16, io mem 0xf7e18000 [ 6.118501] ACPI: Video Device [GFX0] (multi-head: yes rom: no post: no) [ 6.118756] acpi device:42: registered as cooling_device4 [ 6.118858] input: Video Bus as /devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/LNXVIDEO:00/input/input4 [ 6.118900] [drm] radeon kernel modesetting enabled. [ 6.119310] sr 2:0:0:0: Attached scsi generic sg0 type 5 [ 6.119383] sd 6:0:0:0: Attached scsi generic sg1 type 0 [ 6.119387] ehci-pci 0000:00:1a.0: USB 2.0 started, EHCI 1.00 [ 6.119416] usb usb3: New USB device found, idVendor=1d6b, idProduct=0002 [ 6.119417] usb usb3: New USB device strings: Mfr=3, Product=2, SerialNumber=1 [ 6.119417] usb usb3: Product: EHCI Host Controller [ 6.119418] usb usb3: Manufacturer: Linux 3.17.2.1 ehci_hcd [ 6.119418] usb usb3: SerialNumber: 0000:00:1a.0 [ 6.119804] [drm] initializing kernel modesetting (PITCAIRN 0x1002:0x6819 0x174B:0xE218). [ 6.119805] sd 7:0:0:0: Attached scsi generic sg2 type 0 [ 6.119861] hub 3-0:1.0: USB hub found [ 6.119865] hub 3-0:1.0: 2 ports detected [ 6.120036] [drm] register mmio base: 0xF7D00000 [ 6.120075] ehci-pci 0000:00:1d.0: EHCI Host Controller [ 6.120078] ehci-pci 0000:00:1d.0: new USB bus registered, assigned bus number 4 [ 6.120096] ehci-pci 0000:00:1d.0: debug port 2 [ 6.120284] [drm] register mmio size: 262144 [ 6.120389] ATOM BIOS: C40304 [ 6.120510] radeon 0000:01:00.0: VRAM: 2048M 0x0000000000000000 - 0x000000007FFFFFFF (2048M used) [ 6.120580] radeon 0000:01:00.0: GTT: 1024M 0x0000000080000000 - 0x00000000BFFFFFFF [ 6.120648] [drm] Detected VRAM RAM=2048M, BAR=256M [ 6.120710] [drm] RAM width 256bits DDR [ 6.124052] ehci-pci 0000:00:1d.0: irq 23, io mem 0xf7e17000 [ 6.124109] input: PC Speaker as /devices/platform/pcspkr/input/input5 [ 6.124380] [TTM] Zone kernel: Available graphics memory: 8177066 kiB [ 6.124433] [TTM] Zone dma32: Available graphics memory: 2097152 kiB [ 6.124488] [TTM] Initializing pool allocator [ 6.124538] [TTM] Initializing DMA pool allocator [ 6.124608] [drm] radeon: 2048M of VRAM memory ready [ 6.124661] [drm] radeon: 1024M of GTT memory ready. [ 6.124724] [drm] Loading pitcairn Microcode [ 6.124749] Error: Driver 'pcspkr' is already registered, aborting... [ 6.127453] radeon 0000:01:00.0: Direct firmware load for radeon/pitcairn_pfp.bin failed with error -2 [ 6.129389] radeon 0000:01:00.0: Direct firmware load for radeon/pitcairn_me.bin failed with error -2 [ 6.131198] AVX version of gcm_enc/dec engaged. [ 6.131201] radeon 0000:01:00.0: Direct firmware load for radeon/pitcairn_ce.bin failed with error -2 [ 6.131764] radeon 0000:01:00.0: Direct firmware load for radeon/pitcairn_rlc.bin failed with error -2 [ 6.132693] sr 2:0:0:0: [sr0] scsi3-mmc drive: 48x/48x writer dvd-ram cd/rw xa/form2 cdda tray [ 6.132755] cdrom: Uniform CD-ROM driver Revision: 3.20 [ 6.133643] radeon 0000:01:00.0: Direct firmware load for radeon/pitcairn_mc.bin failed with error -2 [ 6.133834] ehci-pci 0000:00:1d.0: USB 2.0 started, EHCI 1.00 [ 6.134133] [drm] radeon/PITCAIRN_mc2.bin: 31100 bytes [ 6.134195] radeon 0000:01:00.0: Direct firmware load for radeon/pitcairn_smc.bin failed with error -2 [ 6.134325] usb usb4: New USB device found, idVendor=1d6b, idProduct=0002 [ 6.134383] usb usb4: New USB device strings: Mfr=3, Product=2, SerialNumber=1 [ 6.134421] alg: No test for __gcm-aes-aesni (__driver-gcm-aes-aesni) [ 6.134491] usb usb4: Product: EHCI Host Controller [ 6.134555] usb usb4: Manufacturer: Linux 3.17.2.1 ehci_hcd [ 6.134602] usb usb4: SerialNumber: 0000:00:1d.0 [ 6.134739] [drm] Internal thermal controller with fan control [ 6.134838] [drm] probing gen 2 caps for device 8086:151 = 261ad03/e [ 6.137565] alg: No test for crc32 (crc32-pclmul) [ 6.138999] hub 4-0:1.0: USB hub found [ 6.139062] hub 4-0:1.0: 2 ports detected [ 6.139306] ACPI Warning: SystemIO range 0x000000000000f040-0x000000000000f05f conflicts with OpRegion 0x000000000000f040-0x000000000000f04f (\_SB_.PCI0.SBUS.SMBI) (20140724/utaddress-258) [ 6.139465] ACPI: If an ACPI driver is available for this device, you should use it instead of the native driver [ 6.145115] [drm] radeon: dpm initialized [ 6.146407] [drm] GART: num cpu pages 262144, num gpu pages 262144 [ 6.146914] [drm] probing gen 2 caps for device 8086:151 = 261ad03/e [ 6.146973] [drm] PCIE gen 3 link speeds already enabled [ 6.152006] [drm] PCIE GART of 1024M enabled (table at 0x0000000000276000). [ 6.152390] radeon 0000:01:00.0: WB enabled [ 6.152444] radeon 0000:01:00.0: fence driver on ring 0 use gpu addr 0x0000000080000c00 and cpu addr 0xffff880037634c00 [ 6.152503] radeon 0000:01:00.0: fence driver on ring 1 use gpu addr 0x0000000080000c04 and cpu addr 0xffff880037634c04 [ 6.152562] radeon 0000:01:00.0: fence driver on ring 2 use gpu addr 0x0000000080000c08 and cpu addr 0xffff880037634c08 [ 6.152620] radeon 0000:01:00.0: fence driver on ring 3 use gpu addr 0x0000000080000c0c and cpu addr 0xffff880037634c0c [ 6.152682] radeon 0000:01:00.0: fence driver on ring 4 use gpu addr 0x0000000080000c10 and cpu addr 0xffff880037634c10 [ 6.153346] radeon 0000:01:00.0: fence driver on ring 5 use gpu addr 0x0000000000075a18 and cpu addr 0xffffc90005fb5a18 [ 6.154410] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013). [ 6.154463] [drm] Driver supports precise vblank timestamp query. [ 6.154526] radeon 0000:01:00.0: radeon: using MSI. [ 6.154592] [drm] radeon: irq initialized. [ 6.154875] iTCO_vendor_support: vendor-support=0 [ 6.155286] intel_rapl: Found RAPL domain package [ 6.155341] intel_rapl: Found RAPL domain core [ 6.155394] intel_rapl: Found RAPL domain uncore [ 6.155766] iTCO_wdt: Intel TCO WatchDog Timer Driver v1.11 [ 6.155843] iTCO_wdt: Found a Panther Point TCO device (Version=2, TCOBASE=0x0460) [ 6.155977] iTCO_wdt: initialized. heartbeat=30 sec (nowayout=0) [ 6.157131] sound hdaudioC0D0: autoconfig: line_outs=3 (0x14/0x15/0x16/0x0/0x0) type:line [ 6.157198] sound hdaudioC0D0: speaker_outs=0 (0x0/0x0/0x0/0x0/0x0) [ 6.157257] sound hdaudioC0D0: hp_outs=1 (0x1b/0x0/0x0/0x0/0x0) [ 6.157315] sound hdaudioC0D0: mono: mono_out=0x0 [ 6.157377] sound hdaudioC0D0: dig-out=0x1e/0x0 [ 6.157434] sound hdaudioC0D0: inputs: [ 6.157492] sound hdaudioC0D0: Front Mic=0x19 [ 6.157550] sound hdaudioC0D0: Rear Mic=0x18 [ 6.157608] sound hdaudioC0D0: Line=0x1a [ 6.197364] input: HDA Intel PCH Front Mic as /devices/pci0000:00/0000:00:1b.0/sound/card0/input7 [ 6.197477] input: HDA Intel PCH Rear Mic as /devices/pci0000:00/0000:00:1b.0/sound/card0/input8 [ 6.197513] input: HDA Intel PCH Line as /devices/pci0000:00/0000:00:1b.0/sound/card0/input9 [ 6.197547] input: HDA Intel PCH Line Out Front as /devices/pci0000:00/0000:00:1b.0/sound/card0/input10 [ 6.197581] input: HDA Intel PCH Line Out Surround as /devices/pci0000:00/0000:00:1b.0/sound/card0/input11 [ 6.197619] input: HDA Intel PCH Line Out CLFE as /devices/pci0000:00/0000:00:1b.0/sound/card0/input12 [ 6.197654] input: HDA Intel PCH Front Headphone as /devices/pci0000:00/0000:00:1b.0/sound/card0/input13 [ 6.197707] input: HDA Intel PCH HDMI/DP,pcm=3 as /devices/pci0000:00/0000:00:1b.0/sound/card0/input14 [ 6.197742] input: HDA Intel PCH HDMI/DP,pcm=7 as /devices/pci0000:00/0000:00:1b.0/sound/card0/input15 [ 6.203285] Adding 3903484k swap on /dev/mapper/debian-swap. Priority:-1 extents:1 across:3903484k SSFS [ 6.238081] BTRFS info (device sdb2): enabling auto defrag [ 6.238143] BTRFS info (device sdb2): disk space caching is enabled [ 6.315580] [drm] ring test on 0 succeeded in 4 usecs [ 6.315642] [drm] ring test on 1 succeeded in 1 usecs [ 6.315696] [drm] ring test on 2 succeeded in 1 usecs [ 6.315758] [drm] ring test on 3 succeeded in 2 usecs [ 6.315821] [drm] ring test on 4 succeeded in 1 usecs [ 6.440842] BUG: unable to handle kernel NULL pointer dereference at 0000000000000090 [ 6.441017] IP: [<ffffffffa04e08c3>] dce6_bandwidth_update+0x43/0x100 [radeon] [ 6.441143] PGD 0 [ 6.441241] Oops: 0000 [#1] SMP [ 6.441380] Modules linked in: snd_hda_codec_hdmi x86_pkg_temp_thermal evdev intel_powerclamp snd_hda_codec_realtek iTCO_wdt intel_rapl iTCO_vendor_support snd_hda_codec_generic acpi_cpufreq(-) coretemp kvm_intel kvm crc32_pclmul ghash_clmulni_intel aesni_intel aes_x86_64 lrw gf128mul glue_helper ablk_helper psmouse cryptd pcspkr serio_raw snd_hda_intel(+) snd_hda_controller sr_mod sg cdrom radeon(+) snd_hda_codec ttm snd_hwdep drm_kms_helper snd_pcm nuvoton_cir video intel_smartconnect drm rc_core battery tpm_tis i2c_algo_bit tpm i2c_i801 snd_timer ehci_pci ehci_hcd snd i2c_core xhci_hcd mei_me soundcore processor button mei usbcore lpc_ich ie31200_edac usb_common mfd_core edac_core thermal_sys fuse autofs4 btrfs xor raid6_pq dm_mod netconsole configfs sd_mod crc_t10dif crct10dif_generic ahci libahci crct10dif_pclmul crct10dif_common crc32c_intel libata scsi_mod r8169 mii shpchp [ 6.445512] CPU: 3 PID: 933 Comm: laptop_mode Not tainted 3.17.2.1 #1 [ 6.445564] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./H77 Pro4/MVP, BIOS P1.70 08/07/2013 [ 6.445622] task: ffff8800c4e0ea00 ti: ffff8800c4e40000 task.ti: ffff8800c4e40000 [ 6.445679] RIP: 0010:[<ffffffffa04e08c3>] [<ffffffffa04e08c3>] dce6_bandwidth_update+0x43/0x100 [radeon] [ 6.445802] RSP: 0018:ffff8800c4e43e40 EFLAGS: 00010246 [ 6.445853] RAX: ffff880419b204b0 RBX: ffff880419b20000 RCX: ffff880419b204e0 [ 6.445905] RDX: 0000000000000000 RSI: 00000000000000c8 RDI: ffff880419b20000 [ 6.445969] RBP: ffff880419b20000 R08: ffff880419b199be R09: 000000000000040e [ 6.446029] R10: 00000000000186a0 R11: ffff880419b199cc R12: 0000000000000000 [ 6.446080] R13: ffff880419b21750 R14: ffff880419b21060 R15: ffff880419b210e0 [ 6.446133] FS: 00007fa34c15f700(0000) GS:ffff88042f380000(0000) knlGS:0000000000000000 [ 6.446193] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 6.446244] CR2: 0000000000000090 CR3: 00000000c4ca9000 CR4: 00000000001407e0 [ 6.446296] Stack: [ 6.446348] ffff880419b20000 0000000000000000 ffff880419b21728 ffff880419b21750 [ 6.446581] ffff880419b21060 ffff880419b210e0 ffffffffa04b87e4 ffff880419b20000 [ 6.446826] 000000000000000c ffff8800c4daf5e0 ffff88041619e000 ffff880419b21728 [ 6.447066] Call Trace: [ 6.447131] [<ffffffffa04b87e4>] ? radeon_pm_compute_clocks+0x634/0x8e0 [radeon] [ 6.447200] [<ffffffffa04b8ffe>] ? radeon_set_dpm_state+0x6e/0xe0 [radeon] [ 6.447255] [<ffffffff81222f23>] ? kernfs_fop_write+0xe3/0x160 [ 6.447307] [<ffffffff811b0bd2>] ? vfs_write+0xb2/0x1f0 [ 6.447359] [<ffffffff811b1722>] ? SyS_write+0x42/0xa0 [ 6.447412] [<ffffffff81528ec8>] ? page_fault+0x28/0x30 [ 6.447467] [<ffffffff81526e2d>] ? system_call_fastpath+0x1a/0x1f [ 6.447518] Code: 95 90 20 00 00 85 d2 0f 8e ce 00 00 00 83 ea 01 48 8d 85 b0 04 00 00 45 31 e4 48 8d 8c d5 b8 04 00 00 66 0f 1f 44 00 00 48 8b 10 <80> ba 90 00 00 00 01 41 83 dc ff 48 83 c0 08 48 39 c8 75 e9 48 [ 6.450591] RIP [<ffffffffa04e08c3>] dce6_bandwidth_update+0x43/0x100 [radeon] [ 6.450709] RSP <ffff8800c4e43e40> [ 6.450759] CR2: 0000000000000090 [ 6.450826] ---[ end trace 8b1b9f8f098a5ef5 ]--- [ 6.450854] usb 4-1: new high-speed USB device number 2 using ehci-pci [ 96.090492] systemd-journald[224]: Received request to flush runtime journal from PID 1 [ 96.534178] RPC: Registered named UNIX socket transport module. [ 96.534244] RPC: Registered udp transport module. [ 96.534301] RPC: Registered tcp transport module. [ 96.534357] RPC: Registered tcp NFSv4.1 backchannel transport module. [ 96.537226] FS-Cache: Loaded [ 96.543651] FS-Cache: Netfs 'nfs' registered for caching [ 96.550885] Installing knfsd (copyright (C) 1996 okir@monad.swb.de). This is with Linux 3.17.2. I can successfully boot the system with radeon.modeset=0 boot option, and when I run run modprobe radeon modeset=1 after that, KMS is activated without any problem. I am using this graphics card: 01:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Pitcairn PRO [Radeon HD 7850] [1002:6819] Downstream bug report: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=767742
(In reply to Frederik Himpe from comment #0) > [ 6.440842] BUG: unable to handle kernel NULL pointer dereference at > 0000000000000090 > [ 6.441017] IP: [<ffffffffa04e08c3>] dce6_bandwidth_update+0x43/0x100 > [radeon] > [ 6.441143] PGD 0 > [ 6.441241] Oops: 0000 [#1] SMP > [ 6.441380] Modules linked in: snd_hda_codec_hdmi x86_pkg_temp_thermal > evdev intel_powerclamp snd_hda_codec_realtek iTCO_wdt intel_rapl > iTCO_vendor_support snd_hda_codec_generic acpi_cpufreq(-) coretemp kvm_intel > kvm crc32_pclmul ghash_clmulni_intel aesni_intel aes_x86_64 lrw gf128mul > glue_helper ablk_helper psmouse cryptd pcspkr serio_raw snd_hda_intel(+) > snd_hda_controller sr_mod sg cdrom radeon(+) snd_hda_codec ttm snd_hwdep > drm_kms_helper snd_pcm nuvoton_cir video intel_smartconnect drm rc_core > battery tpm_tis i2c_algo_bit tpm i2c_i801 snd_timer ehci_pci ehci_hcd snd > i2c_core xhci_hcd mei_me soundcore processor button mei usbcore lpc_ich > ie31200_edac usb_common mfd_core edac_core thermal_sys fuse autofs4 btrfs > xor raid6_pq dm_mod netconsole configfs sd_mod crc_t10dif crct10dif_generic > ahci libahci crct10dif_pclmul crct10dif_common crc32c_intel libata scsi_mod > r8169 mii shpchp > [ 6.445512] CPU: 3 PID: 933 Comm: laptop_mode Not tainted 3.17.2.1 #1 [...] > [ 6.447200] [<ffffffffa04b8ffe>] ? radeon_set_dpm_state+0x6e/0xe0 > [radeon] > [ 6.447255] [<ffffffff81222f23>] ? kernfs_fop_write+0xe3/0x160 > [ 6.447307] [<ffffffff811b0bd2>] ? vfs_write+0xb2/0x1f0 [...] So this is triggered by laptop_mode writing to the dpm_state attribute. Presumably that doesn't happen if the driver fails to initialise at boot (as it will with modeset=0) and is reloaded after booting.
Could this be the same bug?: https://bugzilla.kernel.org/show_bug.cgi?id=83611
Created attachment 108842 [details] [review] possible fix Does this patch help?
I can confirm that this patch fixes the problem: Linux 3.17.2 boots fine with KMS and laptop-mode-tools enabled.
Will this patch be included in Linux 3.18?
(In reply to Frederik Himpe from comment #5) > Will this patch be included in Linux 3.18? Yes. It's already upstream: http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=8efe82ca908400785253c8f0dfcf301e6bd93488
Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.