Created attachment 123732 [details] dmesg.log If I try to go from 30 to 60 Hz refresh rate at a 4k resolution of 3840x2160 results in a 'no input' at my external display with a corresponding OOPs in my dmesg log: [ 83.446091] ------------[ cut here ]------------ [ 83.446194] WARNING: CPU: 2 PID: 452 at drivers/gpu/drm/i915/intel_display.c:13917 skl_max_scale.part.90+0x6d/0x80 [i915] [ 83.446203] WARN_ON_ONCE(!crtc_clock || cdclk < crtc_clock) [ 83.446209] Modules linked in: [ 83.446216] snd_hda_codec_hdmi dell_led snd_hda_codec_realtek snd_hda_codec_generic arc4 snd_soc_skl snd_soc_skl_ipc snd_soc_sst_ipc snd_soc_sst_dsp snd_hda_ext_core snd_soc_sst_match snd_soc_core snd_compress snd_pcm_dmaengine ac97_bus snd_hda_intel dell_laptop snd_hda_codec dell_wmi i2c_designware_platform dell_smbios nls_iso8859_1 i2c_designware_core nls_cp437 dcdbas iwlmvm vfat intel_rapl fat rtsx_pci_ms i915 mac80211 x86_pkg_temp_thermal intel_powerclamp coretemp snd_hda_core uvcvideo snd_hwdep iwlwifi snd_pcm videobuf2_vmalloc snd_timer videobuf2_memops kvm_intel videobuf2_v4l2 drm_kms_helper videobuf2_core kvm cfg80211 pcspkr psmouse snd irqbypass memstick idma64 serio_raw mei_me videodev virt_dma i2c_i801 soundcore mei shpchp media drm intel_pch_thermal intel_lpss_pci mousedev intel_gtt [ 83.446380] evdev joydev input_leds btusb syscopyarea led_class btrtl sysfillrect processor_thermal_device sysimgblt mac_hid fb_sys_fops intel_soc_dts_iosf i2c_algo_bit fan thermal wmi battery i2c_hid hci_uart btbcm btqca video btintel pinctrl_sunrisepoint pinctrl_intel bluetooth rfkill crc16 intel_lpss_acpi intel_lpss int3400_thermal acpi_thermal_rel intel_hid int3403_thermal sparse_keymap int340x_thermal_zone ac button acpi_pad acpi_als fjes kfifo_buf industrialio tpm_tis tpm sch_fq_codel ip_tables x_tables algif_skcipher af_alg hid_multitouch hid_generic usbhid hid dm_crypt dm_mod rtsx_pci_sdmmc mmc_core atkbd libps2 crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel aes_x86_64 lrw gf128mul glue_helper ablk_helper cryptd ahci libahci nvme nvme_core libata xhci_pci rtsx_pci xhci_hcd [ 83.446560] scsi_mod usbcore usb_common i8042 serio xfs crc32c_generic crc32c_intel libcrc32c [ 83.446589] CPU: 2 PID: 452 Comm: Xorg Tainted: G U 4.6.0-rc7-g44549e8 #1 [ 83.446597] Hardware name: Dell Inc. XPS 13 9350/09JHRY, BIOS 1.3.3 03/01/2016 [ 83.446604] 0000000000000286 000000002af38527 ffff88046a2cba20 ffffffff812e34a1 [ 83.446618] ffff88046a2cba70 0000000000000000 ffff88046a2cba60 ffffffff8107a5bb [ 83.446630] 0000365d000008ae ffff88046bf773c0 ffff88046b16ac00 ffff88046a187000 [ 83.446643] Call Trace: [ 83.446667] [<ffffffff812e34a1>] dump_stack+0x63/0x82 [ 83.446677] [<ffffffff8107a5bb>] __warn+0xcb/0xf0 [ 83.446689] [<ffffffff8107a63f>] warn_slowpath_fmt+0x5f/0x80 [ 83.446752] [<ffffffffa0a22cc0>] ? intel_dp_compute_config+0x2c0/0x6a0 [i915] [ 83.446818] [<ffffffffa09ee3ed>] skl_max_scale.part.90+0x6d/0x80 [i915] [ 83.446873] [<ffffffffa09ee4c0>] intel_check_primary_plane+0xc0/0xe0 [i915] [ 83.446936] [<ffffffffa09de9ee>] intel_plane_atomic_check+0x12e/0x1f0 [i915] [ 83.446957] [<ffffffffa083b488>] drm_atomic_helper_check_planes+0x48/0x1d0 [drm_kms_helper] [ 83.447026] [<ffffffffa09f9753>] intel_atomic_check+0x2a3/0x1140 [i915] [ 83.447055] [<ffffffffa05384d8>] drm_atomic_check_only+0x188/0x610 [drm] [ 83.447080] [<ffffffffa0537f8c>] ? drm_atomic_set_crtc_for_connector+0x6c/0x110 [drm] [ 83.447105] [<ffffffffa0538977>] drm_atomic_commit+0x17/0x60 [drm] [ 83.447123] [<ffffffffa083bf81>] drm_atomic_helper_set_config+0x81/0xc0 [drm_kms_helper] [ 83.447160] [<ffffffffa0526e55>] drm_mode_set_config_internal+0x65/0x110 [drm] [ 83.447195] [<ffffffffa052bff8>] drm_mode_setcrtc+0x448/0x560 [drm] [ 83.447222] [<ffffffffa051da12>] drm_ioctl+0x152/0x540 [drm] [ 83.447252] [<ffffffffa052bbb0>] ? drm_mode_setplane+0x1c0/0x1c0 [drm] [ 83.447269] [<ffffffff811f4c0c>] ? __vfs_write+0xcc/0x100 [ 83.447282] [<ffffffff81207fa1>] do_vfs_ioctl+0xa1/0x5b0 [ 83.447292] [<ffffffff81087631>] ? __set_task_blocked+0x41/0xa0 [ 83.447301] [<ffffffff812123f7>] ? __fget+0x77/0xb0 [ 83.447313] [<ffffffff81208529>] SyS_ioctl+0x79/0x90 [ 83.447323] [<ffffffff8108a17e>] ? SyS_rt_sigprocmask+0x8e/0xc0 [ 83.447334] [<ffffffff815c6e32>] entry_SYSCALL_64_fastpath+0x1a/0xa4 [ 83.447377] ---[ end trace 25edcc9116054f9e ]--- [ 83.505895] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe B FIFO underrun My setup is as follows: - Dell XPS 13 9350 - Intel Iris 540 - Display LG 27UD68P-W - DP 1.2 cable See the attached `dmesg` and `lspci -vvnn` output for more information: - dmesg: http://ix.io/DEH - lspci: http://ix.io/DEG My ultimate goal is to drive my external display at 4k with 60 Hz. I figured this should be possible given the listed hardware.
Please add drm.debug=14 module parameter, reproduce the problem, and attach the dmesg to bugzilla.
Created attachment 123819 [details] dmesg with drm.debug=14 The bug reproduced with kernel option 'drm.debug=14'
[ 12.914535] [drm:intel_update_cdclk] Current CD clock rate: 450000 kHz [ 91.861529] [drm:intel_dump_crtc_timings] crtc timings: 533280 3840 3848 3992 4000 2160 2214 2219 2222, type: 0x0 flags: 0x9 Your cdclk is too low for that mode. I have a branch which has the required bits to adjust cdclk dynamically on SKL: git://github.com/vsyrjala/linux.git skl_bxt_cdclk_part_2 Can you test with that branch?
(In reply to Ville Syrjala from comment #3) > [ 12.914535] [drm:intel_update_cdclk] Current CD clock rate: 450000 kHz > [ 91.861529] [drm:intel_dump_crtc_timings] crtc timings: 533280 3840 3848 > 3992 4000 2160 2214 2219 2222, type: 0x0 flags: 0x9 > > Your cdclk is too low for that mode. Why didn't we reject the mode?
(In reply to Jani Nikula from comment #4) > (In reply to Ville Syrjala from comment #3) > > [ 12.914535] [drm:intel_update_cdclk] Current CD clock rate: 450000 kHz > > [ 91.861529] [drm:intel_dump_crtc_timings] crtc timings: 533280 3840 3848 > > 3992 4000 2160 2214 2219 2222, type: 0x0 flags: 0x9 > > > > Your cdclk is too low for that mode. > > Why didn't we reject the mode? The current upstream SKL cdclk code is bad. It sets the max cdclk to something != current cdclk even though we don't actually support changing the frequency.
Created attachment 123848 [details] dmesg of the kernel from the alternative branch
(In reply to Ville Syrjala from comment #3) > [ 12.914535] [drm:intel_update_cdclk] Current CD clock rate: 450000 kHz > [ 91.861529] [drm:intel_dump_crtc_timings] crtc timings: 533280 3840 3848 > 3992 4000 2160 2214 2219 2222, type: 0x0 flags: 0x9 > > Your cdclk is too low for that mode. I have a branch which has the required > bits to adjust cdclk dynamically on SKL: > git://github.com/vsyrjala/linux.git skl_bxt_cdclk_part_2 > > Can you test with that branch? I did and it seems to works, at least the display didn't blank and xrandr reports 60 Hz. Though, I have no way to tell if this is really the case, because my display won't show this information. See the attached dmesg output for more information. I used the same drm.debug settings as before. PS: Is this fix going upstream some time?
(In reply to Oli from comment #7) > (In reply to Ville Syrjala from comment #3) > > [ 12.914535] [drm:intel_update_cdclk] Current CD clock rate: 450000 kHz > > [ 91.861529] [drm:intel_dump_crtc_timings] crtc timings: 533280 3840 3848 > > 3992 4000 2160 2214 2219 2222, type: 0x0 flags: 0x9 > > > > Your cdclk is too low for that mode. I have a branch which has the required > > bits to adjust cdclk dynamically on SKL: > > git://github.com/vsyrjala/linux.git skl_bxt_cdclk_part_2 > > > > Can you test with that branch? > > I did and it seems to works, at least the display didn't blank and xrandr > reports 60 Hz. Though, I have no way to tell if this is really the case, > because my display won't show this information. > > See the attached dmesg output for more information. I used the same > drm.debug settings as before. [ 9.195675] [drm:intel_update_cdclk] Current CD clock rate: 450000 kHz, VCO: 8100000 kHz, ref: 24000 kHz [ 9.195677] [drm:intel_update_max_cdclk] Max CD clock rate: 675000 kHz [ 9.195678] [drm:intel_update_max_cdclk] Max dotclock rate: 675000 kHz [ 70.790172] [drm:intel_dump_crtc_timings] crtc timings: 533280 3840 3848 3992 4000 2160 2214 2219 2222, type: 0x0 flags: 0x9 [ 70.790188] [drm:intel_modeset_checks] New cdclk calculated to be atomic 540000, actual 540000 [ 71.866294] [drm:skl_set_cdclk] Changing CDCLK to 540000 kHz (VCO 8100000 kHz) [ 71.872408] [drm:intel_update_cdclk] Current CD clock rate: 540000 kHz, VCO: 8100000 kHz, ref: 24000 kHz So everything is looking good. > > PS: Is this fix going upstream some time? It's being reviewed now, so should land soonish, I hope.
(In reply to Ville Syrjala from comment #8) > (In reply to Oli from comment #7) > > (In reply to Ville Syrjala from comment #3) > > > [ 12.914535] [drm:intel_update_cdclk] Current CD clock rate: 450000 kHz > > > [ 91.861529] [drm:intel_dump_crtc_timings] crtc timings: 533280 3840 3848 > > > 3992 4000 2160 2214 2219 2222, type: 0x0 flags: 0x9 > > > > > > Your cdclk is too low for that mode. I have a branch which has the required > > > bits to adjust cdclk dynamically on SKL: > > > git://github.com/vsyrjala/linux.git skl_bxt_cdclk_part_2 > > > > > > Can you test with that branch? > > > > I did and it seems to works, at least the display didn't blank and xrandr > > reports 60 Hz. Though, I have no way to tell if this is really the case, > > because my display won't show this information. > > > > See the attached dmesg output for more information. I used the same > > drm.debug settings as before. > > > [ 9.195675] [drm:intel_update_cdclk] Current CD clock rate: 450000 kHz, > VCO: 8100000 kHz, ref: 24000 kHz > [ 9.195677] [drm:intel_update_max_cdclk] Max CD clock rate: 675000 kHz > [ 9.195678] [drm:intel_update_max_cdclk] Max dotclock rate: 675000 kHz > [ 70.790172] [drm:intel_dump_crtc_timings] crtc timings: 533280 3840 3848 > 3992 4000 2160 2214 2219 2222, type: 0x0 flags: 0x9 > [ 70.790188] [drm:intel_modeset_checks] New cdclk calculated to be atomic > 540000, actual 540000 > [ 71.866294] [drm:skl_set_cdclk] Changing CDCLK to 540000 kHz (VCO 8100000 > kHz) > [ 71.872408] [drm:intel_update_cdclk] Current CD clock rate: 540000 kHz, > VCO: 8100000 kHz, ref: 24000 kHz > > So everything is looking good. > > > > > PS: Is this fix going upstream some time? > > It's being reviewed now, so should land soonish, I hope. This has not really something to do with the bug, but how are these numbers to interpret? I mean, shouldn't there be something like a '60' somewhere?
(In reply to Oli from comment #9) > (In reply to Ville Syrjala from comment #8) > > (In reply to Oli from comment #7) > > > (In reply to Ville Syrjala from comment #3) > > > > [ 12.914535] [drm:intel_update_cdclk] Current CD clock rate: 450000 kHz > > > > [ 91.861529] [drm:intel_dump_crtc_timings] crtc timings: 533280 3840 3848 > > > > 3992 4000 2160 2214 2219 2222, type: 0x0 flags: 0x9 > > > > > > > > Your cdclk is too low for that mode. I have a branch which has the required > > > > bits to adjust cdclk dynamically on SKL: > > > > git://github.com/vsyrjala/linux.git skl_bxt_cdclk_part_2 > > > > > > > > Can you test with that branch? > > > > > > I did and it seems to works, at least the display didn't blank and xrandr > > > reports 60 Hz. Though, I have no way to tell if this is really the case, > > > because my display won't show this information. > > > > > > See the attached dmesg output for more information. I used the same > > > drm.debug settings as before. > > > > > > [ 9.195675] [drm:intel_update_cdclk] Current CD clock rate: 450000 kHz, > > VCO: 8100000 kHz, ref: 24000 kHz > > [ 9.195677] [drm:intel_update_max_cdclk] Max CD clock rate: 675000 kHz > > [ 9.195678] [drm:intel_update_max_cdclk] Max dotclock rate: 675000 kHz > > [ 70.790172] [drm:intel_dump_crtc_timings] crtc timings: 533280 3840 3848 > > 3992 4000 2160 2214 2219 2222, type: 0x0 flags: 0x9 > > [ 70.790188] [drm:intel_modeset_checks] New cdclk calculated to be atomic > > 540000, actual 540000 > > [ 71.866294] [drm:skl_set_cdclk] Changing CDCLK to 540000 kHz (VCO 8100000 > > kHz) > > [ 71.872408] [drm:intel_update_cdclk] Current CD clock rate: 540000 kHz, > > VCO: 8100000 kHz, ref: 24000 kHz > > > > So everything is looking good. > > > > > > > > PS: Is this fix going upstream some time? > > > > It's being reviewed now, so should land soonish, I hope. > > This has not really something to do with the bug, but how are these numbers > to interpret? I mean, shouldn't there be something like a '60' somewhere? For the refresh rate? That'd be 'dotclock/htotal/vtotal' so in this case 533280*1000/4000/2222 = 60.
Any progress on this one? An ETA when it will be merged into upstream?
(In reply to Oli from comment #11) > Any progress on this one? An ETA when it will be merged into upstream? We seem to have pushed this a while back http://mid.gmane.org/20160523182136.GY4329@intel.com So it's all in drm-intel-nightly branch of http://cgit.freedesktop.org/drm-intel, headed to v4.8. Thanks for the report, closing. Please reopen if the problem persists with those.
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