From f872b7ca718e34eabdf2b2ece571bff7db6bf164 Mon Sep 17 00:00:00 2001
From: Matthew Dillon <dillon@apollo.backplane.com>
Date: Wed, 22 May 2019 23:27:57 -0700
Subject: [PATCH] kernel - Reduce acpi_ec timeout after failure, silence errors

* Reduce the acpi_ec timeout from 750ms to 100ms after a
  failure.

* Automatically silence... well, all acpi error messages,
  after 10 acpi_ec errors.

* This allows the dell xps-13 to boot in a more reasonable
  period of time and not spew EC errors to the console all
  the time, as a default, without us having to disable EC manually..
---
 sys/dev/acpica/Osd/OsdStream.c |  6 ++++--
 sys/dev/acpica/acpi_ec.c       | 23 +++++++++++++++++++++--
 2 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/sys/dev/acpica/Osd/OsdStream.c b/sys/dev/acpica/Osd/OsdStream.c
index 06defd5022..b8d91032fe 100644
--- a/sys/dev/acpica/Osd/OsdStream.c
+++ b/sys/dev/acpica/Osd/OsdStream.c
@@ -39,7 +39,7 @@
 
 #include <dev/acpica/acpivar.h>
 
-static int acpi_silence_all = 0;
+int acpi_silence_all = 0;
 TUNABLE_INT("debug.acpi.silence_all", &acpi_silence_all);
 SYSCTL_INT(_debug_acpi, OID_AUTO, silence_all, CTLFLAG_RW,
     &acpi_silence_all, 0, "Silence ACPI messages");
@@ -59,5 +59,7 @@ AcpiOsPrintf(const char *Format, ...)
 void
 AcpiOsVprintf(const char *Format, va_list Args)
 {
-    kvprintf(Format, Args);
+    if (acpi_silence_all == 0) {
+	    kvprintf(Format, Args);
+    }
 }
diff --git a/sys/dev/acpica/acpi_ec.c b/sys/dev/acpica/acpi_ec.c
index d586376507..88d0d585de 100644
--- a/sys/dev/acpica/acpi_ec.c
+++ b/sys/dev/acpica/acpi_ec.c
@@ -166,7 +166,8 @@ struct acpi_ec_softc {
 #define EC_POLL_DELAY	50
 
 /* Total time in ms spent waiting for a response from EC. */
-#define EC_TIMEOUT	750
+#define EC_TIMEOUT		750
+#define EC_TIMEOUT_BACKOFF	100
 
 #define EVENT_READY(event, status)			\
 	(((event) == EC_EVENT_OUTPUT_BUFFER_FULL &&	\
@@ -176,6 +177,8 @@ struct acpi_ec_softc {
 
 ACPI_SERIAL_DECL(ec, "ACPI embedded controller");
 
+extern int acpi_silence_all;
+
 static SYSCTL_NODE(_debug_acpi, OID_AUTO, ec, CTLFLAG_RD, NULL, "EC debugging");
 
 static int	ec_burst_mode;
@@ -190,6 +193,16 @@ static int	ec_timeout = EC_TIMEOUT;
 TUNABLE_INT("debug.acpi.ec.timeout", &ec_timeout);
 SYSCTL_INT(_debug_acpi_ec, OID_AUTO, timeout, CTLFLAG_RW, &ec_timeout,
     EC_TIMEOUT, "Total time spent waiting for a response (poll+sleep)");
+static int	ec_timeout_backoff = EC_TIMEOUT_BACKOFF;
+TUNABLE_INT("debug.acpi.ec.timeout_backoff", &ec_timeout);
+SYSCTL_INT(_debug_acpi_ec, OID_AUTO, timeout_backoff, CTLFLAG_RW,
+	&ec_timeout_backoff, EC_TIMEOUT_BACKOFF,
+	"Total time spent waiting for a response (poll+sleep)");
+static int	ec_auto_silence = 10;	/* silence after 10 errors */
+TUNABLE_INT("debug.acpi.ec.auto_silence", &ec_auto_silence);
+SYSCTL_INT(_debug_acpi_ec, OID_AUTO, auto_silence, CTLFLAG_RW,
+	&ec_auto_silence, 1,
+	"Total time spent waiting for a response (poll+sleep)");
 
 #ifndef KTR_ACPI_EC
 #define	KTR_ACPI_EC	KTR_ALL
@@ -934,8 +947,14 @@ EcWaitEvent(struct acpi_ec_softc *sc, EC_EVENT Event, u_int gen_count)
 	    "not getting interrupts, switched to polled mode\n");
 	ec_polled_mode = 1;
     }
-    if (ACPI_FAILURE(Status))
+    if (ACPI_FAILURE(Status)) {
+	ec_timeout = ec_timeout_backoff;
+	if (ec_auto_silence > 0) {
+	    if (--ec_auto_silence <= 0)
+		acpi_silence_all = 1;
+	}
 	KTR_LOG(acpi_ec_timeout);
+    }
     return (Status);
 }
 
-- 
2.41.0