ACPI: EC: Separate delays for MSI hardware

MSI notebooks require very strict delays, while all others
are happy with msleep().

References: http://bugzilla.kernel.org/show_bug.cgi?id=9998

Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 13 insertions, 3 deletions

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index 2fe15060dcdc..ac9dd3b386b1 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -67,7 +67,7 @@ enum ec_command {
 
 #define ACPI_EC_DELAY           500     /* Wait 500ms max. during EC ops */
 #define ACPI_EC_UDELAY_GLK      1000    /* Wait 1ms max. to get global lock */
-#define ACPI_EC_UDELAY          100     /* Wait 100us before polling EC again */
+#define ACPI_EC_CDELAY          10      /* Wait 10us before polling EC */
 
 #define ACPI_EC_STORM_THRESHOLD 8       /* number of false interrupts
                                            per one transaction */
@@ -236,13 +236,23 @@ static int ec_check_sci(struct acpi_ec *ec, u8 state)
         return 0;
 }
 
+static void ec_delay(void)
+{
+        /* EC in MSI notebooks don't tolerate delays other than 550 usec */
+        if (EC_FLAGS_MSI)
+                udelay(ACPI_EC_DELAY);
+        else
+                /* Use shortest sleep available */
+                msleep(1);
+}
+
 static int ec_poll(struct acpi_ec *ec)
 {
         unsigned long delay = jiffies + msecs_to_jiffies(ACPI_EC_DELAY);
-        udelay(ACPI_EC_UDELAY);
+        udelay(ACPI_EC_CDELAY);
         while (time_before(jiffies, delay)) {
                 gpe_transaction(ec, acpi_ec_read_status(ec));
-                udelay(ACPI_EC_UDELAY);
+                ec_delay();
                 if (ec_transaction_done(ec))
                         return 0;
         }