On Mon, Aug 24, 2015 at 11:59:59AM +0300, Mika Westerberg wrote: > On Mon, Aug 24, 2015 at 06:21:47PM +0530, Kasagar, Srinidhi wrote: > > On Fri, Aug 21, 2015 at 04:20:15PM +0300, Mika Westerberg wrote: > > > 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. > > > > Hm..Some internal south devices in Atom platforms does need ~3ms d3_delay > > which we have fixed them as PCI fixups. So, do you think it make sense > > to selectively pick those kind of devices as fixups and remove the > > conditional delay entirely from this part? > > Depends. If we need to add more and more devices to that fixup list, I > don't think it makes sense. Hmm..I see a lot of such existing stuffs and keeps coming.. > > > Apart from touch/i2c what else breaks in T100? > > I suppose HS-UART and SPI both break as well because the interface clock > is disabled after reset. Ok, then we have two options: Let's drop LPSS_NO_D3_DELAY for BYT and duplicate the common devices which are shared between Braswell and BYT & keep LPSS_NO_D3_DELAY only for BSW. OR Use the cpu id to detect the platform which I believe not a good idea.. Because of few devices, I do not think it make sense to compromise on the significant reduction in the resume delay. Srinidhi -- 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
