Re: [PATCH 1/1] nvme: Add quirk for LiteON CL1 devices running FW 220TQ,22001

[Jongpil Jung]

On Tue, Oct 27, 2020 at 01:23:34PM -0700, Keith Busch wrote:
> On Wed, Oct 28, 2020 at 12:54:38AM +0900, Jongpil Jung wrote:
> > suspend.
> > 
> > When NVMe device receive D3hot from host, NVMe firmware will do
> > garbage collection. While NVMe device do Garbage collection,
> > firmware has chance to going incorrect address.
> > In that case, NVMe storage device goes to no device available state.
> > Finally, host can't access the device any more.
> > 
> > Quirk devices will not use simple suspend even if HMB is enabled.
> > In case of poweroff scenario, NVMe receive "PME turn off".
> > So garbage collection will not be happening.
> > 
> > Liteon(SSSTC) will fix the issue, that's why quirk apply on specific
> > vendor id and firmware version.
> 
> This is a concerning quirk. We use the simple suspend when HMB is
> enabled because at least some platforms disable device DMA access in the
> runtime suspend state. Many devices continue to access their HMB while
> in low power, so we can't let both conditions occur concurrently.
> Unless you know for sure this device doesn't access host memory in
> low-power, there will be at least some platform combinations where this
> quirk will fail.
I will submit another patch to check platform.