Hello
Thank you for looking at it.
Regarding reproduction without an out-of-tree modules: the UDL module is
producing the same artifacts.
I had a glance at the github issue. First, "new Intel devices" is quite
vague. Which devices exactly?
Devices from Metor Lake and Arrow Lake family so far. From what we gathered
from users this includes, but is not limited to:
*
Intel(R) Core(TM) Ultra 9 275HX
*
Intel(R) Core(TM) Ultra 7 265HX
*
Intel(R) Core(TM) Ultra 5 235H
*
Intel(R) Core(TM) Ultra 7 155H
*
Intel(R) Core(TM) Ultra 7 265K
The problem occurs only on new hardwre, regardless of the kernel or our
software version. When using any older processor with the same combination of
kernel version with our product/UDL, everything behaves fine.
In the attached output of lspci one can see that the driver being used by
kernel is actually i915, but the xe module is also loaded. That's why we
initially connected that to the xe module.
Second, seems to me there are a lot of people having issues with
non-Intel GPUs as well. What makes you say this is related to i915 or xe
drivers?
While the similar kind of artifacts show under non-Intel GPUs, they only appear
with the EVDI and are not reproducible under the UDL module. Also the time it
takes to heal and the way the artifacts heal on AMD devices makes us think that
this is a different type of issue. We will be looking at that, but maybe you
have any suggestions what to look for?
Regards
Jakub Prussak
________________________________
From: Jani Nikula <[email protected]>
Sent: Monday, November 10, 2025 5:48 PM
To: Jakub Prussak <[email protected]>; [email protected]
<[email protected]>
Cc: PPD-Penguins <[email protected]>; Lucas De Marchi
<[email protected]>; Thomas Hellström
<[email protected]>; Rodrigo Vivi <[email protected]>; Dave
Airlie <[email protected]>; [email protected]
<[email protected]>
Subject: Re: Cache coherency issues when reading from intel Xe buffer.
CAUTION: Email originated externally, do not click links or open attachments
unless you recognize the sender and know the content is safe.
On Thu, 06 Nov 2025, Jakub Prussak <[email protected]> wrote:
> Hello,
>
> For some time, users of DisplayLink USB-3 docking stations face
> corruptions Ubuntu 24.04 on machines with Intel i915+Xe driver (LENOVO
> IdeaPad Pro 5 16IMH9 in our case)
> Machines using only i915 driver are fine.
AFAICT all IdeaPad Pro 5 16IMH9 models have Meteorlake GPU, and you
should be using i915 driver with that. The attached dmesg only appears
to have the i915 driver anyway. So how's the xe driver related here?
> DisplayLink driver is using evdi kernel
> module(https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_DisplayLink_evdi_blob_main_module&d=DwIBAg&c=7dfBJ8cXbWjhc0BhImu8wVIoUFmBzj1s88r8EGyM0UY&r=W1EIKVsQFqx7ACp4Hsw-KtUjZ5imGzUfM_7UN6O5xwk&m=JT0pLpFmiVNTCKbUp1LFei6Pu_3fQPGwh9cESk1coqXMJlS_-DbXDzPYP1hsvJk3&s=Q2kIS6_ZrX18OfHOYKDy3U8IxEF4rEnwgyDofnw08uA&e=
> ) that
> works as drm output slave. It is using drm_prime exported buffers from
> i915 driver.
Mmh, can you reproduce any of this running upstream kernels without
out-of-tree modules? It's highly unlikely anyone from our side would
start debugging scenarios with out-of-tree modules.
> We had checked a way evdi access dma-buf exported buffer, e.g. if it
> is reading it within dma_buf_begin_cpu_access/dma_buf_end_cpu_access.
>
> Also, we ruled out access to the buffer before all dma_fence's on
> drm_plane are signaled.
> Another approach was to wait on dma_resv resv object from
> drm_gem_object's dma_buf_attachment, again with no luck.
> The issue is reproducible with evdi's evdi_gem_object and generic
> drm_gem_shmem_object implementations of drm_gem_object. Corruptions
> are visible with all compositors - XServer, Gnome/mutter, weston.
> Other kernel module facing this issue is udl.
> Nothing was helpful and we suspect some cache coherency issues.
>
> The problem can be reproduced on the latest kernel on computers with
> new Intel devices, and a lot of our users face this problem
> (https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_DisplayLink_evdi_issues_524&d=DwIBAg&c=7dfBJ8cXbWjhc0BhImu8wVIoUFmBzj1s88r8EGyM0UY&r=W1EIKVsQFqx7ACp4Hsw-KtUjZ5imGzUfM_7UN6O5xwk&m=JT0pLpFmiVNTCKbUp1LFei6Pu_3fQPGwh9cESk1coqXMJlS_-DbXDzPYP1hsvJk3&s=LX8y3cnAkcCfx8N45KMlHkwI031dlPc-cy472qvNfwg&e=
> ). The way to reproduce
> it requires installing EVDI module
> (https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_DisplayLink_evdi&d=DwIBAg&c=7dfBJ8cXbWjhc0BhImu8wVIoUFmBzj1s88r8EGyM0UY&r=W1EIKVsQFqx7ACp4Hsw-KtUjZ5imGzUfM_7UN6O5xwk&m=JT0pLpFmiVNTCKbUp1LFei6Pu_3fQPGwh9cESk1coqXMJlS_-DbXDzPYP1hsvJk3&s=Z3Egg6eKXYMKqHu0gc5dsxdjsQCiVGcgbBXYY2h4vUo&e=
> ), loading it and creating a
> virtual screen (this can be achieved with this sample app:
> https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_jakub-2Dprussak-2Dsynaptics_evdipp&d=DwIBAg&c=7dfBJ8cXbWjhc0BhImu8wVIoUFmBzj1s88r8EGyM0UY&r=W1EIKVsQFqx7ACp4Hsw-KtUjZ5imGzUfM_7UN6O5xwk&m=JT0pLpFmiVNTCKbUp1LFei6Pu_3fQPGwh9cESk1coqXMJlS_-DbXDzPYP1hsvJk3&s=19SbXfvkmN-YvqQgJGrJbBi7L07V81Eaq7cIhLRkQaY&e=
> ). Once a virtual
> screen is created, the artifacts should be visible while moving the
> window around on that screen (see the attached picture or user reports
> mentioned earlier). Similar issue appears with devices using UDL
> driver on Intel platform. Attached are device information files and a
> dmesg output when reproducing this issue.
I had a glance at the github issue. First, "new Intel devices" is quite
vague. Which devices exactly? 'lspci -vnn -d :*:0300'. Also we can see
both i915 and xe drivers in some lsmod listings, but there's no info
which drivers are being used with which devices. That's not actionable.
Second, seems to me there are a lot of people having issues with
non-Intel GPUs as well. What makes you say this is related to i915 or xe
drivers?
BR,
Jani.
--
Jani Nikula, Intel
Module Size Used by
hid_elecom 12288 0
usbhid 77824 0
r8153_ecm 12288 0
cdc_ether 24576 1 r8153_ecm
usbnet 61440 2 r8153_ecm,cdc_ether
snd_usb_audio 565248 1
snd_usbmidi_lib 57344 1 snd_usb_audio
snd_ump 45056 1 snd_usb_audio
r8152 135168 1 r8153_ecm
mii 20480 2 usbnet,r8152
ccm 20480 6
rfcomm 94208 0
snd_seq_dummy 12288 0
snd_hrtimer 12288 1
qrtr 49152 2
cmac 12288 2
algif_hash 16384 1
algif_skcipher 12288 1
af_alg 32768 6 algif_hash,algif_skcipher
bnep 32768 2
sch_fq_codel 24576 2
msr 12288 0
snd_ctl_led 24576 0
evdi 90112 2
snd_soc_skl_hda_dsp 16384 4
snd_soc_intel_sof_board_helpers 28672 1 snd_soc_skl_hda_dsp
snd_sof_probes 28672 0
snd_soc_intel_hda_dsp_common 16384 1 snd_soc_intel_sof_board_helpers
xe 3813376 0
drm_gpuvm 49152 1 xe
drm_gpusvm_helper 40960 1 xe
gpu_sched 65536 1 xe
drm_ttm_helper 16384 1 xe
drm_exec 12288 2 drm_gpuvm,xe
drm_suballoc_helper 24576 1 xe
snd_hda_codec_intelhdmi 24576 1
snd_hda_codec_alc269 139264 1
snd_hda_scodec_component 20480 1 snd_hda_codec_alc269
snd_hda_codec_realtek_lib 65536 1 snd_hda_codec_alc269
snd_hda_codec_generic 118784 2 snd_hda_codec_realtek_lib,snd_hda_codec_alc269
snd_soc_dmic 12288 1
binfmt_misc 24576 1
nls_iso8859_1 12288 1
snd_hda_intel 61440 0
snd_sof_pci_intel_mtl 36864 0
snd_sof_intel_hda_generic 36864 1 snd_sof_pci_intel_mtl
soundwire_intel 81920 1 snd_sof_intel_hda_generic
snd_sof_intel_hda_sdw_bpt 20480 1 soundwire_intel
snd_sof_intel_hda_common 188416 3
snd_sof_pci_intel_mtl,snd_sof_intel_hda_sdw_bpt,snd_sof_intel_hda_generic
snd_soc_hdac_hda 20480 1 snd_sof_intel_hda_common
snd_sof_intel_hda_mlink 45056 4
snd_sof_intel_hda_sdw_bpt,soundwire_intel,snd_sof_intel_hda_common,snd_sof_intel_hda_generic
snd_sof_intel_hda 24576 2
snd_sof_intel_hda_common,snd_sof_intel_hda_generic
snd_hda_codec_hdmi 65536 1 snd_hda_codec_intelhdmi
soundwire_cadence 49152 1 soundwire_intel
snd_sof_pci 24576 2 snd_sof_pci_intel_mtl,snd_sof_intel_hda_generic
snd_sof_xtensa_dsp 12288 1 snd_sof_intel_hda_generic
snd_sof 389120 7
snd_sof_pci_intel_mtl,snd_sof_intel_hda_sdw_bpt,snd_sof_pci,snd_sof_intel_hda_common,snd_sof_intel_hda_generic,snd_sof_probes,snd_sof_intel_hda
snd_sof_utils 16384 1 snd_sof
snd_hda_ext_core 32768 5
snd_sof_intel_hda_sdw_bpt,snd_sof_intel_hda_common,snd_soc_hdac_hda,snd_sof_intel_hda_mlink,snd_sof_intel_hda
snd_hda_codec 204800 10
snd_hda_codec_generic,snd_hda_codec_hdmi,snd_hda_intel,snd_soc_intel_hda_dsp_common,snd_hda_codec_realtek_lib,snd_soc_hdac_hda,snd_hda_codec_alc269,snd_sof_intel_hda,snd_soc_skl_hda_dsp,snd_hda_codec_intelhdmi
snd_hda_core 139264 12
snd_hda_codec_generic,snd_hda_codec_hdmi,snd_hda_intel,snd_hda_ext_core,snd_hda_codec,snd_soc_intel_hda_dsp_common,snd_sof_intel_hda_common,snd_hda_codec_realtek_lib,snd_soc_hdac_hda,snd_hda_codec_alc269,snd_sof_intel_hda,snd_hda_codec_intelhdmi
snd_intel_dspcfg 45056 4
snd_hda_intel,snd_sof,snd_sof_intel_hda_common,snd_sof_intel_hda_generic
snd_intel_sdw_acpi 16384 2 snd_intel_dspcfg,snd_sof_intel_hda_generic
snd_soc_acpi_intel_match 139264 3
snd_sof_pci_intel_mtl,snd_soc_intel_sof_board_helpers,snd_sof_intel_hda_generic
snd_soc_acpi_intel_sdca_quirks 12288 1 snd_soc_acpi_intel_match
soundwire_generic_allocation 20480 1 soundwire_intel
snd_soc_acpi 16384 2
snd_soc_acpi_intel_match,snd_sof_intel_hda_generic
snd_hwdep 24576 2 snd_usb_audio,snd_hda_codec
soundwire_bus 1175552 3
soundwire_intel,soundwire_generic_allocation,soundwire_cadence
snd_soc_sdca 81920 2 snd_soc_acpi_intel_sdca_quirks,soundwire_bus
snd_soc_core 409600 9
soundwire_intel,snd_sof,snd_soc_intel_sof_board_helpers,snd_soc_sdca,snd_sof_intel_hda_common,snd_soc_hdac_hda,snd_sof_probes,snd_soc_dmic,snd_soc_skl_hda_dsp
snd_compress 36864 2 snd_soc_core,snd_sof_probes
intel_uncore_frequency 12288 0
ac97_bus 12288 1 snd_soc_core
intel_uncore_frequency_common 20480 1 intel_uncore_frequency
snd_pcm_dmaengine 20480 1 snd_soc_core
x86_pkg_temp_thermal 16384 0
intel_powerclamp 24576 0
snd_pcm 200704 14
snd_hda_codec_hdmi,snd_hda_intel,snd_usb_audio,snd_hda_codec,soundwire_intel,snd_sof,snd_soc_sdca,snd_sof_intel_hda_common,snd_compress,snd_sof_intel_hda_generic,snd_soc_core,snd_sof_utils,snd_hda_core,snd_pcm_dmaengine
coretemp 24576 0
iwlmvm 831488 0
snd_seq_midi 24576 0
kvm_intel 352256 0
mac80211 1773568 1 iwlmvm
snd_seq_midi_event 16384 1 snd_seq_midi
libarc4 12288 1 mac80211
kvm 1433600 1 kvm_intel
snd_rawmidi 57344 3 snd_seq_midi,snd_usbmidi_lib,snd_ump
processor_thermal_device_pci 16384 0
processor_thermal_device 24576 1 processor_thermal_device_pci
processor_thermal_wt_hint 16384 2
processor_thermal_device_pci,processor_thermal_device
btusb 77824 0
platform_temperature_control 20480 1 processor_thermal_device
snd_seq 118784 9 snd_seq_midi,snd_seq_midi_event,snd_seq_dummy
processor_thermal_soc_slider 16384 1 processor_thermal_device
uvcvideo 135168 0
btmtk 28672 1 btusb
processor_thermal_rfim 40960 1 processor_thermal_device
intel_pmc_core 151552 0
btrtl 32768 1 btusb
videobuf2_vmalloc 20480 1 uvcvideo
processor_thermal_rapl 16384 1 processor_thermal_device
snd_seq_device 16384 4 snd_seq,snd_seq_midi,snd_ump,snd_rawmidi
intel_rapl_msr 20480 0
cmdlinepart 16384 0
mei_gsc_proxy 16384 0
uvc 12288 1 uvcvideo
irqbypass 16384 1 kvm
btbcm 24576 1 btusb
intel_rapl_common 53248 2 intel_rapl_msr,processor_thermal_rapl
iwlwifi 622592 1 iwlmvm
videobuf2_memops 16384 1 videobuf2_vmalloc
snd_timer 53248 3 snd_seq,snd_hrtimer,snd_pcm
polyval_clmulni 12288 0
processor_thermal_wt_req 12288 1 processor_thermal_device
btintel 69632 1 btusb
spi_nor 163840 0
ideapad_laptop 53248 0
videobuf2_v4l2 36864 1 uvcvideo
ghash_clmulni_intel 12288 0
pmt_telemetry 16384 1 intel_pmc_core
processor_thermal_power_floor 12288 2
processor_thermal_device_pci,processor_thermal_device
mtd 98304 3 spi_nor,cmdlinepart
pmt_discovery 16384 1 pmt_telemetry
snd 139264 32
snd_ctl_led,snd_hda_codec_generic,snd_seq,snd_seq_device,snd_hda_codec_hdmi,snd_hwdep,snd_hda_intel,snd_usb_audio,snd_usbmidi_lib,snd_hda_codec,snd_sof,snd_soc_sdca,snd_timer,snd_hda_codec_realtek_lib,snd_compress,snd_hda_codec_alc269,snd_soc_core,snd_ump,snd_pcm,snd_rawmidi
videobuf2_common 86016 4
videobuf2_vmalloc,videobuf2_v4l2,uvcvideo,videobuf2_memops
i2c_i801 36864 0
aesni_intel 98304 6
pmt_class 20480 2 pmt_telemetry,pmt_discovery
mei_me 53248 1
platform_profile 20480 2 ideapad_laptop,processor_thermal_soc_slider
soundcore 16384 2 snd_ctl_led,snd
i2c_mux 12288 1 i2c_i801
intel_hid 32768 0
spi_intel_pci 12288 0
int3403_thermal 16384 0
intel_pmc_ssram_telemetry 16384 1 intel_pmc_core
int3400_thermal 24576 0
processor_thermal_mbox 12288 4
processor_thermal_power_floor,processor_thermal_wt_req,processor_thermal_rfim,processor_thermal_wt_hint
videodev 360448 2 videobuf2_v4l2,uvcvideo
rapl 20480 0
intel_cstate 20480 0
mc 81920 5
videodev,snd_usb_audio,videobuf2_v4l2,uvcvideo,videobuf2_common
bluetooth 1003520 32 btrtl,btmtk,btintel,btbcm,bnep,btusb,rfcomm
wmi_bmof 12288 0
cfg80211 1384448 3 iwlmvm,iwlwifi,mac80211
intel_vpu 282624 0
crc8 12288 1 soundwire_cadence
mei 172032 3 mei_gsc_proxy,mei_me
spi_intel 32768 1 spi_intel_pci
i2c_smbus 20480 1 i2c_i801
igen6_edac 28672 0
int340x_thermal_zone 16384 2 int3403_thermal,processor_thermal_device
acpi_tad 20480 0
intel_vsec 24576 3 intel_pmc_ssram_telemetry,pmt_telemetry,xe
sparse_keymap 12288 2 intel_hid,ideapad_laptop
acpi_pad 184320 0
acpi_thermal_rel 20480 1 int3400_thermal
joydev 32768 0
input_leds 12288 0
i915 4657152 13
mac_hid 12288 0
serio_raw 20480 0
drm_buddy 28672 2 xe,i915
ttm 126976 3 drm_ttm_helper,xe,i915
drm_display_helper 282624 2 xe,i915
cec 98304 3 drm_display_helper,xe,i915
rc_core 73728 1 cec
i2c_algo_bit 16384 2 xe,i915
parport_pc 53248 0
ppdev 24576 0
lp 32768 0
parport 73728 3 parport_pc,lp,ppdev
efi_pstore 12288 0
nfnetlink 20480 1
dmi_sysfs 20480 0
autofs4 57344 2
hid_sensor_custom 28672 0
hid_sensor_hub 28672 1 hid_sensor_custom
intel_ishtp_hid 28672 0
ucsi_acpi 12288 0
typec_ucsi 69632 1 ucsi_acpi
typec 114688 1 typec_ucsi
hid_multitouch 36864 0
hid_generic 12288 0
rtsx_pci_sdmmc 36864 0
nvme 61440 2
nvme_core 229376 3 nvme
i2c_hid_acpi 12288 0
video 77824 3 ideapad_laptop,xe,i915
intel_ish_ipc 32768 0
thunderbolt 528384 1 typec
i2c_hid 40960 1 i2c_hid_acpi
rtsx_pci 143360 1 rtsx_pci_sdmmc
intel_lpss_pci 28672 0
nvme_keyring 20480 1 nvme_core
intel_lpss 12288 1 intel_lpss_pci
intel_ishtp 69632 2 intel_ishtp_hid,intel_ish_ipc
nvme_auth 28672 1 nvme_core
idma64 20480 0
hkdf 12288 1 nvme_auth
hid 270336 8
i2c_hid,hid_elecom,usbhid,hid_multitouch,hid_sensor_hub,snd_soc_sdca,intel_ishtp_hid,hid_generic
pinctrl_meteorlake 28672 1
wmi 24576 3 video,wmi_bmof,ideapad_laptop
00:02.0 VGA compatible controller [0300]: Intel Corporation Meteor Lake-P
[Intel Arc Graphics] [8086:7d55] (rev 08) (prog-if 00 [VGA controller])
Subsystem: Lenovo Meteor Lake-P [Intel Arc Graphics] [17aa:3cc9]
Flags: bus master, fast devsel, latency 0, IRQ 202, IOMMU group 0
Memory at 408c000000 (64-bit, prefetchable) [size=16M]
Memory at 4000000000 (64-bit, prefetchable) [size=256M]
Expansion ROM at 000c0000 [virtual] [disabled] [size=128K]
Capabilities: [40] Vendor Specific Information: Len=0c <?>
Capabilities: [70] Express Root Complex Integrated Endpoint, MSI 00
Capabilities: [ac] MSI: Enable+ Count=1/1 Maskable+ 64bit+
Capabilities: [d0] Power Management version 3
Capabilities: [100] Null
Capabilities: [110] Process Address Space ID (PASID)
Capabilities: [200] Address Translation Service (ATS)
Capabilities: [420] Physical Resizable BAR
Capabilities: [320] Single Root I/O Virtualization (SR-IOV)
Capabilities: [400] Latency Tolerance Reporting
Kernel driver in use: i915
Kernel modules: i915, xe
