On Fri, Aug 21, 2015 at 09:36:41AM +0300, Mika Westerberg wrote: > On Fri, Aug 21, 2015 at 05:41:52PM +0530, Kasagar, Srinidhi wrote: > > On Thu, Aug 20, 2015 at 03:38:05PM +0300, Mika Westerberg wrote: > > > +Heikki > > > > > > On Thu, Aug 20, 2015 at 10:46:07PM +0530, Srinidhi Kasagar wrote: > > > > LPSS devices in Braswell and Baytrail does not need the default > > > > 10ms d3_delay imposed by PCI specification. Removing this > > > > unnecessary delay significantly reduces the resume time > > > > (~200ms on Braswell/Cherrytrail) on these platforms. > > > > > > > > Signed-off-by: Srinidhi Kasagar <srinidhi.kasagar@xxxxxxxxx> > > > > Signed-off-by: Kumar P Mahesh <mahesh.kumar.p@xxxxxxxxx> > > > > > > Have you tested this on Asus T100? The delay was actually needed in > > > order to restore the context IIRC. > > > > Sorry, I do not have T100 h/w :( > > OK. We have one and I'm going to test this patch on it. In particular > the T100 needed to have these delays otherwise writes failed. The patch does not apply on top of v4.2-rc7 or linux-pm/bleeding-edge. So I just unconditionally set the delay to 0 for all LPSS devices on T100. Having msleep(0) seems to be enough and the touch panel including I2C host controller runtime resumes just fine :-) If I remove msleep() completely then things break apart and runtime resuming the touch panel triggers this: [ 46.143111] i2c_hid i2c-ATML1000:00: i2c_hid_set_power [ 46.145758] i2c_hid i2c-ATML1000:00: __i2c_hid_command: cmd=fb 00 00 08 [ 46.148483] i2c_designware 80860F41:05: Unknown Synopsys component type: 0x00000000 [ 46.252125] i2c_designware 80860F41:05: timeout in enabling adapter [ 47.254426] i2c_designware 80860F41:05: controller timed out So clearly it needs some delay but it does not have to be 10ms. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
