2010/11/1 David Vrabel <david.vrabel@xxxxxxx>: > On 29/10/2010 21:18, Linus Walleij wrote: >> This patch modifies the MMC core code to optionally call the >> set_ios() operation on the driver with the clock frequency set >> to 0 (gate) after a grace period of at least 8 MCLK cycles, then >> restore it (ungate) before any new request. This gives >> the driver the option to shut down the MCI clock to the MMC/SD >> card when the clock frequency is 0, i.e. the core has stated >> that the MCI clock does not need to be generated. > > With SDIO cards, 1 bit mode needs to be set on the controller otherwise > many controllers cannot detect card interrupts. Do you mean generally, or just when disabling the clock? I don't quite get this part... > Also some v2.00 SDIO cards in 4-bit mode will not generate card > interrupts unless they are clocked (the spec v2.00 doesn't require them > to be able to but v3.00 does). OK I think it is better to disable clocking off SDIO cards altogether for now. > I would suggest a white list of v2.00 > cards that can generate interrupts asynchronousy. Hm... does people maintain such lists? Sounds tricksy. Better avoid it for the time being. Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
