[CCing the regression list, as it should be in the loop for regressions: https://docs.kernel.org/admin-guide/reporting-regressions.html] [Note: part of this is now handled here: https://lore.kernel.org/all/59b13c93-6637-3050-c145-31be0d6c12c9@xxxxxxxxxxx/] [TLDR: I'm adding this report to the list of tracked Linux kernel regressions; the text you find below is based on a few templates paragraphs you might have encountered already in similar form.] On 14.09.23 18:26, Thomas Richard wrote: > > After switching to Linux 6.6-rc1, i met an issue during suspend to idle > with 8250_omap driver (no_console_suspend is set). > The driver fails to suspend the uart port used for the serial console so > the suspend sequence is stopped. > > [ 114.629197] port 2800000.serial:0.0: PM: calling > pm_runtime_force_suspend+0x0/0x134 @ 114, parent: 2800000.serial:0 > [ 114.639617] port 2800000.serial:0.0: PM: > pm_runtime_force_suspend+0x0/0x134 returned 0 after 2 usecs > [ 114.648739] omap8250 2800000.serial: PM: calling > omap8250_suspend+0x0/0xf4 @ 114, parent: bus@100000 > [ 114.657861] omap8250 2800000.serial: PM: dpm_run_callback(): > omap8250_suspend+0x0/0xf4 returns -16 > [ 114.666808] omap8250 2800000.serial: PM: omap8250_suspend+0x0/0xf4 > returned -16 after 8951 usecs > [ 114.675580] omap8250 2800000.serial: PM: failed to suspend: error -16 > [ 114.682011] PM: suspend of devices aborted after 675.644 msecs > [ 114.687833] PM: start suspend of devices aborted after 681.777 msecs > [ 114.694175] PM: Some devices failed to suspend, or early wake event > detected > > The following sequence is used to suspend to idle: > $ echo 1 > /sys/power/pm_debug_messages > $ echo 1 > /sys/power/pm_print_times > $ echo 8 > /proc/sys/kernel/printk > $ echo 0 > /sys/module/printk/parameters/console_suspend > $ echo enabled > > /sys/devices/platform/bus@100000/2800000.serial/tty/ttyS2/power/wakeup > $ echo s2idle > /sys/power/mem_sleep > $ echo mem > /sys/power/state > > The regression was introduced in commit 20a41a62618d "serial: 8250_omap: > Use force_suspend and resume for system suspend" > > Before commit 20a41a62618d, omap8250_suspend returned 0. > Now pm_runtime_force_suspend is called and its return code is used by > omap8250_suspend. > > static int omap8250_suspend(struct device *dev) > { > struct omap8250_priv *priv = dev_get_drvdata(dev); > struct uart_8250_port *up = serial8250_get_port(priv->line); > int err; > > serial8250_suspend_port(priv->line); > > err = pm_runtime_resume_and_get(dev); > if (err) > return err; > if (!device_may_wakeup(dev)) > priv->wer = 0; > serial_out(up, UART_OMAP_WER, priv->wer); > err = pm_runtime_force_suspend(dev); > flush_work(&priv->qos_work); > > return err; > } > > The pm_runtime_force_suspend function calls omap8250_runtime_suspend > which returns -EBUSY because console suspend was disabled (which is my > case), as explained in the code. > > /* > * When using 'no_console_suspend', the console UART must not be > * suspended. Since driver suspend is managed by runtime suspend, > * preventing runtime suspend (by returning error) will keep device > * active during suspend. > */ > if (priv->is_suspending && !console_suspend_enabled) { > if (up && uart_console(&up->port)) > return -EBUSY; > } > > The port is used by the console, so we don't want to suspend it (console > suspend was disabled). > Of course, if console_suspend is enabled and messages are disabled there > is no issue. Thanks for the report. To be sure the issue doesn't fall through the cracks unnoticed, I'm adding it to regzbot, the Linux kernel regression tracking bot: #regzbot ^introduced 20a41a62618d #regzbot title serial: 8250_omap: suspend issue with console_suspend disabled #regzbot monitor: https://lore.kernel.org/all/59b13c93-6637-3050-c145-31be0d6c12c9@xxxxxxxxxxx/ #regzbot ignore-activity This isn't a regression? This issue or a fix for it are already discussed somewhere else? It was fixed already? You want to clarify when the regression started to happen? Or point out I got the title or something else totally wrong? Then just reply and tell me -- ideally while also telling regzbot about it, as explained by the page listed in the footer of this mail. Developers: When fixing the issue, remember to add 'Link:' tags pointing to the report (the parent of this mail). See page linked in footer for details. Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat) -- Everything you wanna know about Linux kernel regression tracking: https://linux-regtracking.leemhuis.info/about/#tldr That page also explains what to do if mails like this annoy you.
