freeman.liu wrote:Semaphore is clear when a writing operation is finished, and it' done automatically
At the end of the function snd_intel8x0_codec_semaphore. If we
couldn't get the semaphore in 1 ms, we'll reset the register and
return EBUSY. But to reset the register, we should do a
iaputword ( chip, 0, 0 ), according to the datasheet, write any
value the this register will reset the register.
But in the code, what we did is iagetword ( chip, 0 ).
At that point, we don't want to reset the semaphore but to access a dummy AC'97 register so that the semaphore flag is cleared even if we actually got the semaphore (from the igetbyte in the printk). (The iagetword/iaputword functions access AC'97 registers, not ICH registers.)
by the hardware. I think you have misunstandard the code, the printk is just print
out the sema register and global-status register for debug.
Look at the comment after the iagetword. And read the ac97 specification.
Read the ac97 reset register will return the value. write any value to it will reset the
ac97 registers. When code run to this point there must be some error in the hardware,
so we need a reset.
HTH Clemens
--
Best regards
Freeman Liu
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