[SeaBIOS] [PATCH] Support for booting from LSI Logic LSI53C1030, SAS1068, SAS1068e

[Paolo Bonzini]

On 27/01/2016 18:30, Kevin O'Connor wrote:
> On Wed, Jan 27, 2016 at 06:19:43PM +0100, Paolo Bonzini wrote:
>> On 27/01/2016 18:15, Kevin O'Connor wrote:
>>> Oh, I understand and agree that recovery isn't worth while.  My
>>> concern is that a hardware error here will appear as a silent hang.
>>> Breaking out of the loop eventually, calling warn_timeout(), and
>>> returning an error code has the benefit of some debugging from seabios
>>> and likely some strong error messages from the calling app.
>>>
>>> As I'm more interested in the debugging then the recovery, a simple
>>> addition like this would be an improvement IMO:
>>>
>>>     u32 end = calc_timeout(30000);  // 30 second max timeout
>>>     for (;;) {
>>>         ...
>>>         if (timer_check(end)) {
>>>             warn_timeout();
>>>             return DISK_RET_ECONTROLLER;
>>>         }
>>>         usleep(50);
>>>     }
>>
>> I understood this to be your proposal.  The problem is that I wouldn't
>> be able to send any further requests later, because of the way the HBA
>> is programmed.
> 
> I'm a bit confused.  Without my proposal, the machine will silently
> busy loop forever and thus also wont be able to send any further
> requests.
> 
> The only difference, as I see it, is whether or not we report the
> problem.

The difference is that with this proposal you would definitely not be
able to recover; without it, you'll get an error (good) but you'll also
get an error if the timeout was spurious.  In that case, if you do not
have a timeout the behavior is a little better.

I think the best would be to handle all drivers in the same way, and
configure the timeout at Kconfig time.  What do you think?  Are there
drivers that do read/write timeouts?

Paolo