On Thu, 2017-04-06 at 14:12 +0200, Ludovic Desroches wrote: > On Tue, Apr 04, 2017 at 05:50:50PM +0100, Ben Hutchings wrote: > > On Tue, 2017-03-28 at 14:30 +0200, Greg Kroah-Hartman wrote: > > > 4.4-stable review patch. If anyone has any objections, please let me know. > > > > > > ------------------ > > > > > > From: Adrian Hunter <adrian.hunter@xxxxxxxxx> > > > > > > commit e2ebfb2142acefecc2496e71360f50d25726040b upstream. > > > > > > Disabling interrupts for even a millisecond can cause problems for some > > > devices. That can happen when sdhci changes clock frequency because it > > > waits for the clock to become stable under a spin lock. > > > > > > The spin lock is not necessary here. Anything that is racing with changes > > > to the I/O state is already broken. The mmc core already provides > > > synchronization via "claiming" the host. > > [...] > > > > In mainline, drivers/mmc/host/sdhci-of-at91.c has a slightly different > > version of this code that seems to have the same issue. In 4.4 there's > > another (conditional) mdelay(1) further up this function that seems to > > be related to that hardware, and probably ought to have an unlock/lock > > around it. > > Right, how do you want to proceed? Do you want me to send a patch on top > of it to manage this extra mdelay? This change doesn't appear to break anything; I'm just saying that it's an incomplete fix. The other case where there's a delay with IRQs disabled should be fixed with an additional patch. Ben. -- Ben Hutchings Software Developer, Codethink Ltd.