Re: [Qemu-devel] [PATCH 2/3 v6] Replace bdrv_* to bdrv_aio_* functions in DMA mode in fdc.c

[Kevin Wolf]

Am 16.05.2012 10:23, schrieb Zhi Hui Li:
> On 2012年05月15日 17:38, Paolo Bonzini wrote:
>> Il 15/05/2012 11:33, Kevin Wolf ha scritto:
>>>>> which blindly overwrites status2.  Hence the new code was not written
>>>>> based on it.  However, the new code is untested as far as I know.
>>> In the thread of an earlier version of this series, I said that a qtest
>>> for floppy is required. This only confirms it.
>>
>> The problem with writing a qtest is that the spec is incredibly complex
>> and obscure.  It's probably even better to rip out code that cannot be
>> tested properly, so you don't have to test it at all...
>>
>> (Mostly tongue-in-cheek of course.  A qtest for basic read/write in PIO
>> and DMA modes is indeed a very good idea).
>>
>> Paolo
>>
>>
> 
> Yes , I think maybe Paolo is right.
> 
> Because the spec is incredibly complex and obscure and I am newer.
> To write the whole code's qtest beyond my ability. I am afraid I can't 
> finish it. so I want only do a qtest about basic read/write in PIO
> and DMA modes. I don't know whether it is OK.

Don't worry, any test is better than no test. We should try to add a
qtest for basic operation to fdc-test.c. More detailed tests can be
added later, or maybe we find good additions during review.

I know that the floppy controller spec is hard to read. Writing test
cases basically means translating it into clearer requirements.

> (I don't know whether we can use qtest to replace the real test, 
> especially on PIO mode 's test.)

In theory yes, qtest can do everything if you have a complete set of
test cases to cover the whole spec. In practice it will just help to
find regressions earlier (floppy isn't tested very often manually).

Kevin