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<base href="https://bugs.freedesktop.org/" />
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<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - blank screen at 4k@60Hz DP 1.2"
href="https://bugs.freedesktop.org/show_bug.cgi?id=93980">93980</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>blank screen at 4k@60Hz DP 1.2
</td>
</tr>
<tr>
<th>Product</th>
<td>DRI
</td>
</tr>
<tr>
<th>Version</th>
<td>XOrg git
</td>
</tr>
<tr>
<th>Hardware</th>
<td>Other
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>medium
</td>
</tr>
<tr>
<th>Component</th>
<td>DRM/Intel
</td>
</tr>
<tr>
<th>Assignee</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>alinm.elena@gmail.com
</td>
</tr>
<tr>
<th>QA Contact</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
<tr>
<th>CC</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr></table>
<p>
<div>
<pre>So I try to connect my external display to my dell xps 9350 skylake
works fine with DP1.1 <a href="mailto:3840x2160@30.00">3840x2160@30.00</a>
However if I move to DPI1.2 while xrandr reports the 60Hz as available and
prefered, trying to select it results in a blank screen and this error in log
[14888.696042] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU
pipe B FIFO underrun
this is with 4.5.0-rc1-2.gc7bac4c
there is a kernel trace in logs but i think is unrelated to the aformentioned
error.
[ 2441.732603] [drm:intel_dp_start_link_train [i915]] *ERROR* 5.4 Gbps link
rate without HBR2/TPS3 support
[ 2441.736534] [drm] Reducing the compressed framebuffer size. This may lead to
less power savings than a non-reduced-size. Try to increase stolen memory size
if available in BIOS.
[ 2441.999859] ------------[ cut here ]------------
[ 2441.999896] WARNING: CPU: 2 PID: 2188 at
../drivers/gpu/drm/i915/intel_pm.c:3544 skl_update_other_pipe_wm+0x14d/0x150
[i915]()
[ 2441.999897] WARN_ON(!wm_changed)
[ 2441.999898] Modules linked in:
[ 2441.999900] fuse hidp cmac ecb rfcomm af_packet bnep hid_generic btusb
btrtl uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_core
usbhid videodev hid_multitouch snd_hda_codec_hdmi dell_led
snd_hda_codec_realtek snd_hda_codec_generic nls_iso8859_1 snd_hda_intel
nls_cp437 x86_pkg_temp_thermal intel_powerclamp coretemp vfat snd_hda_codec fat
snd_hda_core snd_hwdep kvm_intel snd_pcm kvm irqbypass crct10dif_pclmul
crc32_pclmul brcmfmac dell_laptop rtsx_pci_ms brcmutil snd_timer dcdbas
i2c_designware_platform ghash_clmulni_intel i2c_designware_core aesni_intel
dell_wmi cfg80211 memstick aes_x86_64 snd lrw gf128mul glue_helper ablk_helper
cryptd idma64 pcspkr joydev mei_me hci_uart soundcore i2c_i801 virt_dma btbcm
shpchp mei btqca btintel intel_lpss_pci processor_thermal_device
intel_soc_dts_iosf
[ 2441.999941] thermal fan bluetooth rfkill pinctrl_sunrisepoint pinctrl_intel
intel_lpss_acpi intel_lpss int3400_thermal int3403_thermal acpi_thermal_rel
int340x_thermal_zone battery wmi intel_hid acpi_pad ac acpi_als tpm_tis
sparse_keymap kfifo_buf tpm industrialio i915 rtsx_pci_sdmmc mmc_core
crc32c_intel i2c_algo_bit xhci_pci drm_kms_helper syscopyarea sysfillrect
sysimgblt xhci_hcd fb_sys_fops serio_raw drm rtsx_pci nvme mfd_core usbcore
usb_common video i2c_hid button fjes sg efivarfs
[ 2441.999969] CPU: 2 PID: 2188 Comm: X Tainted: G U W
4.5.0-rc1-2.gc7bac4c-default #1
[ 2441.999971] Hardware name: Dell Inc. XPS 13 9350/0VM5NC, BIOS 1.2.3
01/08/2016
[ 2441.999972] ffffffffa03b5700 ffff88046e2ff988 ffffffff81390cb9
ffff88046e2ff9d0
[ 2441.999975] ffff88046e2ff9c0 ffffffff8107c712 ffff88046e2ffa44
ffff88046a379bd4
[ 2441.999977] ffff88046aa9e000 ffff88005ebf1b78 ffff88046b5ad000
ffff88046e2ffa20
[ 2441.999980] Call Trace:
[ 2441.999988] [<ffffffff8101a115>] try_stack_unwind+0x175/0x190
[ 2441.999995] [<ffffffff81019069>] dump_trace+0x69/0x3a0
[ 2441.999999] [<ffffffff8101a17b>] show_trace_log_lvl+0x4b/0x60
[ 2442.000002] [<ffffffff810194ac>] show_stack_log_lvl+0x10c/0x180
[ 2442.000005] [<ffffffff8101a215>] show_stack+0x25/0x50
[ 2442.000010] [<ffffffff81390cb9>] dump_stack+0x4b/0x72
[ 2442.000015] [<ffffffff8107c712>] warn_slowpath_common+0x82/0xc0
[ 2442.000020] [<ffffffff8107c79c>] warn_slowpath_fmt+0x4c/0x50
[ 2442.000032] [<ffffffffa02f047d>] skl_update_other_pipe_wm+0x14d/0x150
[i915]
[ 2442.000047] [<ffffffffa02f05e3>] skl_update_wm+0x163/0x630 [i915]
[ 2442.000060] [<ffffffffa02f3e2e>] intel_update_watermarks+0x1e/0x30 [i915]
[ 2442.000081] [<ffffffffa035cf11>] haswell_crtc_enable+0x321/0x8c0 [i915]
[ 2442.000102] [<ffffffffa0359bf4>] intel_atomic_commit+0x694/0xac0 [i915]
[ 2442.000120] [<ffffffffa0189067>] drm_atomic_commit+0x37/0x60 [drm]
[ 2442.000129] [<ffffffffa026e586>] drm_atomic_helper_set_config+0x76/0xb0
[drm_kms_helper]
[ 2442.000141] [<ffffffffa0178682>] drm_mode_set_config_internal+0x62/0x100
[drm]
[ 2442.000154] [<ffffffffa017ce5d>] drm_mode_setcrtc+0x3cd/0x4e0 [drm]
[ 2442.000163] [<ffffffffa016e712>] drm_ioctl+0x152/0x540 [drm]
[ 2442.000167] [<ffffffff8121a912>] do_vfs_ioctl+0x92/0x580
[ 2442.000171] [<ffffffff8121ae79>] SyS_ioctl+0x79/0x90
[ 2442.000175] [<ffffffff816c50f6>] entry_SYSCALL_64_fastpath+0x16/0x75
[ 2442.001869] DWARF2 unwinder stuck at entry_SYSCALL_64_fastpath+0x16/0x75
[ 2442.001872] Leftover inexact backtrace:
[ 2442.001875] ---[ end trace a05b3ea76533043e ]---</pre>
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