mfd: intel-lpss: Remove D3cold delay

BugLink: https://bugs.launchpad.net/bugs/1840075
Goodix touchpad may drop its first couple input events when
i2c-designware-platdrv and intel-lpss it connects to took too long to
runtime resume from runtime suspended state.

This issue happens becuase the touchpad has a rather small buffer to
store up to 13 input events, so if the host doesn't read those events in
time (i.e. runtime resume takes too long), events are dropped from the
touchpad's buffer.

The bottleneck is D3cold delay it waits when transitioning from D3cold
to D0, hence remove the delay to make the resume faster. I've tested
some systems with intel-lpss and haven't seen any regression.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202683
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
(cherry picked from commit 76380a607ba0b28627c9b4b55cd47a079a59624b linux-next)
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Acked-by: Connor Kuehl <connor.kuehl@canonical.com>
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

diff --git a/drivers/mfd/intel-lpss-pci.c b/drivers/mfd/intel-lpss-pci.c
index 299a4bb48e341a87c8b35244dc79f39881d377ca..ec91b2dbdd3b55a5b139d349ee5c15addfb959ff 100644 (file)
--- a/drivers/mfd/intel-lpss-pci.c
+++ b/drivers/mfd/intel-lpss-pci.c
@@ -39,6 +39,8 @@ static int intel_lpss_pci_probe(struct pci_dev *pdev,
        info->mem = &pdev->resource[0];
        info->irq = pdev->irq;
 
+       pdev->d3cold_delay = 0;
+
        /* Probably it is enough to set this for iDMA capable devices only */
        pci_set_master(pdev);
        pci_try_set_mwi(pdev);