[systemd-devel] systemd doesn't see ttyPS0 devices from udev

[Andrei Borzenkov]

On Tue, Sep 22, 2020 at 2:53 PM Mantas Mikulėnas <grawity at gmail.com> wrote:
>
> On Tue, Sep 22, 2020 at 1:46 PM Andrei Borzenkov <arvidjaar at gmail.com> wrote:
>>
>> On Tue, Sep 22, 2020 at 1:35 PM ZhouPeng <zhoupengwork01 at 163.com> wrote:
>> >
>> > Hi all,
>> >
>> > When I use Fedora image as rootfs on Xilinx PYNQ-Z2, I encountered the issue  when use the /dev/ttyPS0.
>> > I think the issue is because systemd and udev on fedora can didn't detect ttyPS0 properly. Do I need to install any other package or do some special configuration?
>> >
>> > **systemd version the issue has been seen with**
>> > udevadm --version
>> > 237
>> > systemd-udev.riscv64                     237-1.0.riscv64.fc28
>> >
>> >
>> > **Unexpected behaviour you saw**
>> > We can see ttyPS0 boots ok in the kernel boot period:
>> > [    0.180000] console [ttyPS0] enabledat MMIO 0xe0000000 (irq = 2, base_baud = 6250000) is a xuartps
>> > [    0.180000] console [ttyPS0] enabled
>> >
>> > But, when boot into systemd, it failed on dev ttyPS0:
>> > [ TIME ] Timed out waiting for device dev-ttyPS0.device. // **here**
>>
>> systemd only monitors for devices with "sysemd" tag. Tags are assigned
>> by udev rules. You should add rule to assign tag to ttyPS0. I have no
>> idea what it is, but something like
>>
>> ACTION!="remove", KERNEL=="ttyPS0", TAG+="systemd"
>>
>> should do it. Whether this should go upstream depends on how common
>> this device is.
>
>
> Well yes, but that should have been already covered by the existing upstream rules:
>
> 99-systemd.rules:12:SUBSYSTEM=="tty", KERNEL=="tty[a-zA-Z]*|hvc*|xvc*|hvsi*|ttysclp*|sclp_line*|3270/tty[0-9]*", TAG+="systemd"
>

Are you sure ttyPS0 has the "tty" subsystem?