Re: sd_mod or usb-storage fails to read a single good block (was: ehci_hcd fails to read a single good block)

[Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>]

On Tue, 17 Apr 2012, Norman Diamond wrote:

> Yes it does look like changing this bridge to CAPACITY_HEURISTICS
> from FIX_CAPACITY is likely to help a bit.

That's easy enough.

> I think that heuristics should also accept multiples of 63 even if
> the total is odd.  This doesn't solve everything but will probably
> help more.

Okay, if nobody objects.

> I think that handling of FIX_CAPACITY should check for multiples of
> 63 and report the apparent likelihood that FIX_CAPACITY probably
> wasn't the right setting for the bridge (if it's a bridge).  This
> doesn't solve everything but will probably help more.

The FIX_CAPACITY code runs in a different module.  It has no way to 
know whether the device is a bridge or not.

> The addition of TEST_CAPACITY doesn't solve everything but will
> probably help more.

That will require a certain amount of work, with the possibility of 
breaking some systems.  I'd rather not do it if there's no clear and 
pressing need.

Alan Stern

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