"Overclock" for sdcard reader?

[mirh]

So.. is this where the cool steam deck kernel guys are at? (is it @antheas?)
Long story short yesterday I realized the bottleneck of pretty much most consumer SD hardware, and I was trying to spread the word.

Steam deck uses the OZ711LV2 controller which in turn should equal to O2Micro/BayHubTech 1217:8621 (of note that while the driver and the device id have been around for more than a decade, this specific pcie bridge chip only popped up in the last years).
It's kinda shitty (or at least whatever shadow of an official spec it has claims it's just "SD3") but AFAICT it does the usual top 90MB/s speed so it's already on the frontier.

https://github.com/torvalds/linux/blob/master/drivers/mmc/host/sdhci-pci-o2micro.c
This is the driver to tinker with, and I'm not posting on the official tracker because I see they already have enough glitches with corrupted cards there (for as much it's probably just people with old or cheap cards).