[PATCH 1/4] um: irqs: process outstanding IRQs when unblocking signals

[Benjamin Beichler]

Am 20.10.2023 um 11:59 schrieb Benjamin Berg:
>>
>> I also noticed this problem, but after a discussion with Johannes Berg
>> about this, we come to the conclusion, that all drivers with interrupts
>> need to deal with time travel mode via their own time travel handler.
>> What I actually did, was to write a trivial handler for e.g., the serial
>> line, which simply only call time_travel_add_irq_event(ev).
> 
> Yes, we could instead just assert that we do not have any IRQ without a
> timetravel handler. We really shouldn't have, but we do have one for
> stdin unfortunately (which is at least used by the hostap hwsim tests,
> so we might want to not remove it until we have a different solution).
> 
> What we could do is just add an stdin timetravel handler as you have
> done, but print a warning when the stdin IRQ is registered[1]. And
> then, if someone tries to register an IRQ without a time-travel handler
> we just panic(), it should never happen.
Can you explain, why a time travel handler for stdin may be bad? It 
sounds like you want to avoid it, but I see no immediate problem.

> 
> Benjamin
> 
> [1] We'll also need to set stdin to be a "null" channel and then
> somehow avoid registering the IRQ in that case.
> 

-- 
M.Sc. Benjamin Beichler

Universität Rostock, Fakultät für Informatik und Elektrotechnik
Institut für Angewandte Mikroelektronik und Datentechnik

University of Rostock, Department of CS and EE
Institute of Applied Microelectronics and CE

Albert-Einstein-Str. 26
18059 Rostock
Deutschland/Germany

phone: +49 (0) 381 498 - 7278
email: Benjamin.Beichler at uni-rostock.de
www: http://www.imd.uni-rostock.de/

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