Bug 1911763 - repeated keycode 227 from Video bus
Summary: repeated keycode 227 from Video bus
Alias: None
Product: Fedora
Classification: Fedora
Component: kernel
Version: 33
Hardware: x86_64
OS: Linux
Target Milestone: ---
Assignee: Kernel Maintainer List
QA Contact: Fedora Extras Quality Assurance
Depends On:
TreeView+ depends on / blocked
Reported: 2020-12-31 03:37 UTC by Sampson Fung
Modified: 2021-06-30 15:29 UTC (History)
18 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Last Closed: 2021-06-30 15:29:57 UTC
Type: Bug

Attachments (Terms of Use)
journalctl --no-hostname -k (91.83 KB, text/plain)
2020-12-31 03:37 UTC, Sampson Fung
no flags Details

Description Sampson Fung 2020-12-31 03:37:49 UTC
Created attachment 1743355 [details]
journalctl --no-hostname -k

1. Please describe the problem:
A repeated text appeared as "^@" is interfering input in text mode, even login can fail.

2. What is the Version-Release number of the kernel:

3. Did it work previously in Fedora? If so, what kernel version did the issue
   *first* appear?  Old kernels are available for download at
   https://koji.fedoraproject.org/koji/packageinfo?packageID=8 :

4. Can you reproduce this issue? If so, please provide the steps to reproduce
   the issue below:

Boot to multi-user.target
run evtest (ver 1.34)
while waiting to choose an input, repeated "^@" appears, which will abort evtest once enter is pressed.
if choose an input fast enough, evtest goes into listen mode
a.  choose Keyboard, no keycode detected, but "^@" keep appearing
b.  choose Video Bus, keycode 227 is detected everytime a "^@" appears

5. Does this problem occur with the latest Rawhide kernel? To install the
   Rawhide kernel, run ``sudo dnf install fedora-repos-rawhide`` followed by
   ``sudo dnf update --enablerepo=rawhide kernel``:


6. Are you running any modules that not shipped with directly Fedora's kernel?:


7. Please attach the kernel logs. You can get the complete kernel log
   for a boot with ``journalctl --no-hostname -k > dmesg.txt``. If the
   issue occurred on a previous boot, use the journalctl ``-b`` flag.

ps.  adding radeon.runpm=0 to kernel parameter reduce the frequency of the repeated "^@" appearing.

Hardware:  Dell Vostro 3350 notebook

Comment 1 Hans de Goede 2021-01-01 13:36:45 UTC

Thank you for your bug report.

You should be able to stop these key-presses from being reported by adding the following to the Linux kernel commandline:


You can do this by running the following command:

sudo grubby --update-kernel=ALL --args="video.report_key_events=2"

Please run the following command:

grep . /sys/class/dmi/id/* 2> /dev/null

As normal user and copy and paste the output here. Then I can add a quirk for your model laptop to the kernel to suppress these keyboard events automatically without needing  a kernel commandline option.

One question before I add a quirk to the kernel for this. Have you run Linux on this laptop before and if yes, did you also have this issue when you ran Linux before?



Comment 2 Sampson Fung 2021-01-02 07:37:01 UTC
Thank you very much for the quick response.

The keycode is stopped following your instructions.

Below is the output:
$grep . /sys/class/dmi/id/* 2>/dev/null
/sys/class/dmi/id/bios_vendor:Dell Inc.
/sys/class/dmi/id/board_vendor:Dell Inc.
/sys/class/dmi/id/chassis_vendor:Dell Inc.
/sys/class/dmi/id/chassis_version:Not Specified
/sys/class/dmi/id/product_name:Vostro 3350
/sys/class/dmi/id/product_sku:To be filled by O.E.M.
/sys/class/dmi/id/product_version:Not Specified
/sys/class/dmi/id/sys_vendor:Dell Inc.

No.  This is the first time I can put Fedora to this machine.  But I notice this keycode issue almost immediately.

Comment 3 Hans de Goede 2021-01-06 11:25:09 UTC
Good to hear that the kernel-commandline option helps.

After taking a closer look I believe that this is an issue with the radeon driver, and ideally we should be able to fix this there rather then adding a quirk for this. I've asked a colleague who knows the radeon driver better to take a look.

Comment 4 Hans de Goede 2021-06-30 15:29:57 UTC
Sorry for being quite slow with following up on this.

I've had a discussion with the amdgpu devs about this, hoping that we could find a solution which would not involve adding a quirk, but we've not been able to come up with anything there.

So I've gone ahead and submitted a quirk upstream, so that future kernel version will automatically set video.report_key_events=2 when running in a Dell Vostro 3350:

This means that eventually (once this change gets integrated into the kernels Fedora ships) you should be able to remove the "video.report_key_events=2" from the kernel commandline and things should keep working, but for now you still need it (and it does no harm to keep it around).

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