[PATCH] nvme-pci: prevent SK Hynix PE8000 from using Write Zeroes command

[Christoph Hellwig]

On Wed, Feb 10, 2021 at 10:11:15PM +0000, Chaitanya Kulkarni wrote:
> On 2/10/21 5:20 AM, Christoph Hellwig wrote:
> > MDTS vs Write Zeroes is a common misconception.  We had that discussion
> > in the NVMe working group, and while the text should pretty clear that
> > MDTS only applies to data transfers many implementators did not understand
> > that, which is why we added the clarification you quoted.
> >
> > Also the next NVMe spec will allow devices to advertise an explicit
> > Write Zeroes limit, take a look at TP4040 from the "NVM Express 1.4 Ratified
> > TPs" at https://nvmexpress.org/developers/nvme-specification/.
> >
> > So I think limiting to MDTS unless the new WZSL is set might be a fail
> > safe option, even if it is more pessimistic than what the spec says.
> >
> > I'd also love to retest most Write Zeroes quirks with that in place.
> 
> Do you prefer some variant of the following patch (totally untested)? OR
> something else ?

Somwhat.  As said I suspect defaulting to MDTS with a big fat comment
might make most sense unless the new WZSL is set.