Re: [PATCH] ACPI / LPSS: Ignore 10ms delay for Braswell and Baytrail

[Mika Westerberg <mika.westerberg@linux.intel.com>]

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@intel.com>
> > > Signed-off-by: Kumar P Mahesh <mahesh.kumar.p@intel.com>
> > 
> > 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.

> > 
> > Also you are saying Braswell and Baytrail but...
> > 
> > > ---
> > >  drivers/acpi/acpi_lpss.c |   59 ++++++++++++++++++++++++++++++++++++----------
> > >  1 file changed, 46 insertions(+), 13 deletions(-)
> > > 
> 
> [...]
> 
> > > @@ -219,13 +247,13 @@ static const struct acpi_device_id acpi_lpss_device_ids[] = {
> > >  	{ "8086228E", LPSS_ADDR(bsw_spi_dev_desc) },
> > >  	{ "808622C1", LPSS_ADDR(byt_i2c_dev_desc) },
> > >  
> > > -	{ "INT3430", LPSS_ADDR(lpt_dev_desc) },
> > > -	{ "INT3431", LPSS_ADDR(lpt_dev_desc) },
> > > -	{ "INT3432", LPSS_ADDR(lpt_i2c_dev_desc) },
> > > -	{ "INT3433", LPSS_ADDR(lpt_i2c_dev_desc) },
> > > -	{ "INT3434", LPSS_ADDR(lpt_uart_dev_desc) },
> > > -	{ "INT3435", LPSS_ADDR(lpt_uart_dev_desc) },
> > > -	{ "INT3436", LPSS_ADDR(lpt_sdio_dev_desc) },
> > > +	{ "INT3430", LPSS_ADDR(bsw_lpt_dev_desc) },
> > > +	{ "INT3431", LPSS_ADDR(bsw_lpt_dev_desc) },
> > > +	{ "INT3432", LPSS_ADDR(bsw_lpt_i2c_dev_desc) },
> > > +	{ "INT3433", LPSS_ADDR(bsw_lpt_i2c_dev_desc) },
> > > +	{ "INT3434", LPSS_ADDR(bsw_lpt_uart_dev_desc) },
> > > +	{ "INT3435", LPSS_ADDR(bsw_lpt_uart_dev_desc) },
> > > +	{ "INT3436", LPSS_ADDR(bsw_lpt_sdio_dev_desc) },
> > 
> > ... these are Broadwell devices. Have you tested that this won't break
> > existing Broadwell systems?
> 
> You mean these are Broadwell devices too? As of now I have
> tested these devices to be working on Braswell and Cherrytrail.

Yes, the ACPI IDs you are changing above are Broadwell ACPI IDs
(INT34xx).