Re: [PATCH] arm64: configs: defconfig: Convert TISCI to modules

[Thomas Richard <thomas.richard@bootlin.com>]

Hi Nishanth,

On 9/10/26 3:44 PM, Nishanth Menon wrote:
> Now that all relevant drivers have are ready, convert the
> TISCI drivers to modules. This impacts all K3 platforms for
> boot, recommendation (based on empirical evidence) is to use
> deferred_probe_timeout=60 in kernel command line to allow for driver
> probes to complete successfully based on the initrd used.
> 
It's maybe a bit late, but I did test your patch (linux next-20260923)
on J7200. Indeed with default deferred_probe_timeout value I got some
deferred probe.

[   16.869217] platform 2830000.serial: deferred probe pending: (reason
unknown)
[   16.869241] platform 24c0000.timer: deferred probe pending: (reason
unknown)

Using deferred_probe_timeout=60 fixes sometimes deferred probe for
24c0000.timer, but never not for 2830000.serial.

[   68.582069] platform 2830000.serial: deferred probe pending: (reason
unknown)
[   68.582094] platform 24c0000.timer: deferred probe pending: (reason
unknown)
[   68.582128] ti_sci_pm_domains
44083000.system-controller:power-controller: sync_state() pending due to
24c0000.timer
[   68.582144] ti_sci_pm_domains
44083000.system-controller:power-controller: sync_state() pending due to
2830000.serial

But switching all TISCI drivers to 'y' fixed them. Looks like an
ordering issue.

I also did test suspend-to-ram, it works as expected. Fun fact, doing a
suspend-to-ram allows to probe these 2 missing devices during resume. I
guess it confirms a timing/ordering issue during the boot. At the end of
the resume, no device anymore in /sys/kernel/debug/devices_deferred.

[  124.053571] Restarting tasks: Starting
[  124.053861] Restarting tasks: Done
[  124.053907] random: crng reseeded on system resumption
[  124.053970] PM: suspend exit
[  124.058833] 2830000.serial: ttyS0 MMIO:0x0000000002830000 (irq = 700,
base_baud = 3000000) is a 8250

Best Regards,
Thomas