Following appears with kernel 4.4.36 .
Maybe as a result of following patch ?
drm/radeon: Ensure vblank interrupt is enabled on DPMS transition to on
[ 5.331666] Can't enable IRQ/MSI because no handler is installed [ 5.331842] ------------[ cut here ]------------ [ 5.331847] WARNING: at c048a53c [verbose debug info unavailable] [ 5.331851] Modules linked in: [ 5.331859] CPU: 0 PID: 1 Comm: swapper Not tainted 4.4.36-sam460ex-jm #1 [ 5.331864] task: ea848000 ti: ea84c000 task.ti: ea84c000 [ 5.331867] NIP: c048a53c LR: c048a53c CTR: 00000000 [ 5.331870] REGS: ea84d6e0 TRAP: 0700 Not tainted (4.4.36-sam460ex-jm) [ 5.331879] MSR: 00029000 <CE,EE,ME> CR: 24008222 XER: 00000000 [ 5.331914] [ 5.331914] GPR00: c048a53c ea84d790 ea848000 00000034 00000000 00000000 c0ea7a2c 00000000 [ 5.331914] GPR08: 00029000 00000800 ea84c000 ea84d790 24008222 00000000 eaa8096c 00000001 [ 5.331914] GPR16: eaacd9d4 c08e6c20 00000000 00000000 c0c678d7 00000000 c0da0000 ea982048 [ 5.331914] GPR24: c08f24c0 ea982108 eaa80984 ea9d4d80 eaa80800 eaa80800 eabdc000 ea982000 [ 5.331932] NIP [c048a53c] si_irq_set+0x28/0x9e4 [ 5.331937] LR [c048a53c] si_irq_set+0x28/0x9e4 [ 5.331938] Call Trace: [ 5.331945] [ea84d790] [c048a53c] si_irq_set+0x28/0x9e4 (unreliable) [ 5.331958] [ea84d7f0] [c0409b20] atombios_crtc_dpms+0x8c/0x104 [ 5.331964] [ea84d810] [c0409bb4] atombios_crtc_commit+0x1c/0x38 [ 5.331972] [ea84d820] [c03c9d90] drm_crtc_helper_set_mode+0x36c/0x410 [ 5.331978] [ea84d9f0] [c03ca628] drm_crtc_helper_set_config+0x6dc/0x934 [ 5.331991] [ea84da60] [c0423a70] radeon_crtc_set_config+0x50/0xf8 [ 5.332007] [ea84da80] [c03e47b0] drm_mode_set_config_internal+0x5c/0xe0 [ 5.332021] [ea84daa0] [c03d4704] restore_fbdev_mode+0x20c/0x25c [ 5.332030] [ea84dad0] [c03d61ec] drm_fb_helper_restore_fbdev_mode_unlocked+0x40/0x8c [ 5.332036] [ea84daf0] [c03d6284] drm_fb_helper_set_par+0x4c/0x60 [ 5.332047] [ea84db00] [c0388144] fbcon_init+0x318/0x410 [ 5.332056] [ea84db50] [c03b3024] visual_init+0xac/0xf8 [ 5.332063] [ea84db60] [c03b487c] do_bind_con_driver+0x1e8/0x2d8 [ 5.332070] [ea84dbb0] [c03b4cd0] do_take_over_console+0x19c/0x1ac [ 5.332075] [ea84dbe0] [c03878bc] do_fbcon_takeover+0x80/0xe4 [ 5.332087] [ea84dbf0] [c003c3fc] notifier_call_chain+0x60/0x94 [ 5.332094] [ea84dc10] [c003c71c] __blocking_notifier_call_chain+0x50/0x68 [ 5.332104] [ea84dc30] [c038f3a8] register_framebuffer+0x248/0x26c [ 5.332111] [ea84dc90] [c03d65b4] drm_fb_helper_initial_config+0x31c/0x39c [ 5.332120] [ea84dcd0] [c042bc78] radeon_fbdev_init+0xcc/0xf8 [ 5.332126] [ea84dcf0] [c0425dd0] radeon_modeset_init+0x5a8/0x938 [ 5.332132] [ea84dd50] [c040316c] radeon_driver_load_kms+0xcc/0x184 [ 5.332138] [ea84dd70] [c03df0b8] drm_dev_register+0x84/0xc8 [ 5.332144] [ea84dd90] [c03e0e78] drm_get_pci_dev+0xf4/0x18c [ 5.332156] [ea84ddb0] [c03719e4] pci_device_probe+0x88/0xe8 [ 5.332164] [ea84ddd0] [c05436f4] driver_probe_device+0x130/0x290 [ 5.332170] [ea84de00] [c05438cc] __driver_attach+0x78/0xa0 [ 5.332188] [ea84de20] [c0541bec] bus_for_each_dev+0x90/0xa0 [ 5.332193] [ea84de50] [c0542dc8] bus_add_driver+0xe0/0x1f0 [ 5.332199] [ea84de70] [c054400c] driver_register+0xb4/0xf8 [ 5.332207] [ea84de90] [c00016f8] do_one_initcall+0x11c/0x1a0 [ 5.332214] [ea84df00] [c0d08acc] kernel_init_freeable+0x130/0x1cc [ 5.332220] [ea84df30] [c0001cf4] kernel_init+0x14/0xf8 [ 5.332228] [ea84df40] [c000ade4] ret_from_kernel_thread+0x5c/0x64 [ 5.332230] Instruction dump: [ 5.332241] 7c0803a6 4bb7c1ec 9421ffa0 7c0802a6 bdc10018 90010064 894313d0 2f8a0000 [ 5.332251] 40be001c 3c60c0c7 38631c16 483ea6c5 <0fe00000> 3860ffea 480009ac 89431aa8 [ 5.332274] ---[ end trace 3fbb08226210324a ]--- [ 5.413526] Console: switching to colour frame buffer device 240x67