Chris Ball wrote: > Hi David, > > > Why? Is this for a specific card that doesn't support > > asynchronous card interrupts while in 4-bit mode? If so, I'd > > suggest a card quirk for this and only switch modes for these > > cards. > > (As a check that we're on the same page -- sdio_disable_wide() is only > called if MMC_PM_KEEP_POWER is true, which means the system is going > to be suspended but the card will remain externally powered without > its clock.) > > Under the circumstances above, it's a requirement of the SDIO spec > that moving to 1-bit mode must happen before stopping the clock if > the interrupt mechanism is to be used to wake the host, and the > chipset we've been using (Via VX855) fails to generate a wakeup if > the switch isn't made. Do you have experience of another chipset > that doesn't need the switch to 1-bit mode for a clockless wakeup? I couldn't find anything in the SDIO specification (you know the section number?). Part A2 has a requirement that the controller be placed into 1-bit mode but this doesn't mean that the card has to be. Maybe it's not really a big deal, a single command only costs a few 10s of microseconds anyway. 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
