So is there any kind of device able to use A2 cards at the rated performance yet...

megous · on July 22, 2019

I don't know. It's a bit of a bummer.

I imagine Android would benefit the most (and phones also don't suffer from sudden power outages, which is the biggest risk with enabling this), so someone may try looking if mmc core in androind kernel has patches to support this.

aidenn0 · on July 22, 2019

My phone will reboot randomly; depending on what layer the reboot happens at, there may be no flush command sent to the card.

megous · on July 22, 2019

No worries, I checked it a few minutes ago, and android doesn't support this either.

asveikau · on July 22, 2019

> and phones also don't suffer from sudden power outages,

Phone batteries die, and the battery remaining percentages are only an estimate so writing code to react to that condition can be fickle.

cesarb · on July 22, 2019

> and phones also don't suffer from sudden power outages

Perhaps you have never dropped your phone, but in my experience, on a dropped phone the battery cover and the battery often go flying.

pixl97 · on July 22, 2019

I will say that at least most flagship phones these days have internal batteries.

metildaa · on July 23, 2019

Flagships have been skyrocketing in price and are losing marketshare to the midrange segment, which almost always has removable storage, and often has a swappable battery.

cat199 · on July 22, 2019

> What good is a performance designation (A2) if no device in the real world supports it?

this is often the case for new hardware specs/protocols..

see also: any SATA/SCSI rev N+1, TCQ/NCQ, UASP, PCI n+1, etc.

geerlingguy · on July 22, 2019

But in all those cases (I have used most of them), there was _some_ way a consumer could acquire hardware (and drivers) to use the tech. It might've been expensive, but I could go out and buy an SATA card, or SCSI 2, or whatever.

With A2, so far I have not seen any way any consumer (or anyone, really) could achieve 2000/4000 IOPS.

That would be like selling a SATA 2400 drive for 2x the cost of an SATA 600 drive... but not selling any kind of controller that could use more than SATA 600 bandwidth.

megous · on July 22, 2019

It should be possible to patch the kernel. If I had an A2 card, I'd try. It's probably just a question of detecting card features on card plug-in and sending a command to enable the cache.

Spec/code is open. I'm just sort of surprised noone tried it yet.

mcbridematt · on July 23, 2019

You will probably need a true SD/MMC controller to use any "new" commands, such as a smartphone or embedded target (such as the RPi). USB or other bridges used on notebooks are unlikely to have support for it (especially as they convert MMC/SD to a USB-storage class device)

fragmede · on July 22, 2019

Assuming the cards with the A2 designation do actually support the claimed speeds, support will (eventually) be added, and the faster performance will be observed, on the Pi and other host devices.