Linus Walleij wrote: > 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... Just when disabling the clock. >> 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. Ok. David -- David Vrabel, Senior Software Engineer, Drivers CSR, Churchill House, Cambridge Business Park, Tel: +44 (0)1223 692562 Cowley Road, Cambridge, CB4 0WZ http://www.csr.com/ Member of the CSR plc group of companies. CSR plc registered in England and Wales, registered number 4187346, registered office Churchill House, Cambridge Business Park, Cowley Road, Cambridge, CB4 0WZ, United Kingdom -- 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
