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linux-surface / surface-aggregator-module

Linux ACPI and Platform Drivers for Surface Devices using the Surface Aggregator Module over Surface Serial Hub (Surface Book 2, Surface Pro 2017, Surface Laptop, and Newer)
GNU General Public License v2.0
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Occasional ENXIO on gpiod_to_irq #31

Open PandorasFox opened 4 years ago

PandorasFox commented 4 years ago

Occasionally (say, 1 in every 10 boots) my SL3A will get ENXIO returned on the gpiod_to_irq in the ssh module.

Using my usb keyboard to unload/reload the module has it init properly later, so I'm assuming that it's just a weird race condition.

qzed commented 4 years ago

That's a bit weird. Looking at https://elixir.bootlin.com/linux/v5.4.8/source/drivers/gpio/gpiolib.c#L3811 would suggest that the gpiochip might not be fully set up yet, which would be collaborated by your finding that it's a race condition. It's interesting because I had a conversation with Hans de Goede regarding the button driver, who mentioned that in x86 GPIOs should be fully set up once "normal" modules load (https://lkml.org/lkml/2019/10/5/104, although that's related to gpiod_get in that case). Even more so because the surface_sam_ssh module is loaded via late_initcall, so even later due to some DMA setup issues we had before. I guess that would kind of suggest something going wrong in the GPIO driver again. I'm not quite sure yet though.