On Fri, May 14, 2021 at 08:03:20PM +0200, Volker Rümelin wrote:
The comment above the yield() function suggests that yield()
allows interrupts for a short time. Currently this is only true
if seabios was built without CONFIG_THREADS or if yield() is
called from the main thread. Change the code to always call
check_irqs() in yield().
I'm confused about the failure scenario you describe here, as yield()
really should always allow irqs to run prior to returning. When
called from a "background thread" it will not directly enable irqs,
but it will always cycle through all "threads" before returning. Thus
the "main thread" should always be reached and when it runs yield() it
will permit irqs to run.
Am I missing something?
Hi Kevin,
the main thread calls run_thread() to create a background thread, adds
it behind main thread in the thread list and immediately executes the
background thread until the background thread calls yield(). All
background threads in the thread list run in sequence and call yield()
until the last background thread yields to main thread. The main thread
has not reached wait_threads(), which means it will create another
background thread and run it. This will repeat until all background
threads are created. You can see until now the main thread did not call
yield() but the background threads ran several times. The main thread
calls yield() for the first time in wait_threads().
With best regards,
Volker
-Kevin
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