Patch "Input: applespi - don't wait for responses to commands indefinitely." has been added to the 5.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    Input: applespi - don't wait for responses to commands indefinitely.

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     input-applespi-don-t-wait-for-responses-to-commands-.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 68ecdf1e489cdca22a8e8dc4afe6874baaf2539b
Author: Ronald Tschalär <ronald@xxxxxxxxxxxxx>
Date:   Fri Feb 19 11:10:51 2021 -0800

    Input: applespi - don't wait for responses to commands indefinitely.
    
    [ Upstream commit 0ce1ac23149c6da939a5926c098c270c58c317a0 ]
    
    The response to a command may never arrive or it may be corrupted (and
    hence dropped) for some reason. While exceedingly rare, when it did
    happen it blocked all further commands. One way to fix this was to
    do a suspend/resume. However, recovering automatically seems like a
    nicer option. Hence this puts a time limit (1 sec) on how long we're
    willing to wait for a response, after which we assume it got lost.
    
    Signed-off-by: Ronald Tschalär <ronald@xxxxxxxxxxxxx>
    Link: https://lore.kernel.org/r/20210217190718.11035-1-ronald@xxxxxxxxxxxxx
    Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/input/keyboard/applespi.c b/drivers/input/keyboard/applespi.c
index d38398526965..a4b7422de534 100644
--- a/drivers/input/keyboard/applespi.c
+++ b/drivers/input/keyboard/applespi.c
@@ -48,6 +48,7 @@
 #include <linux/efi.h>
 #include <linux/input.h>
 #include <linux/input/mt.h>
+#include <linux/ktime.h>
 #include <linux/leds.h>
 #include <linux/module.h>
 #include <linux/spinlock.h>
@@ -400,7 +401,7 @@ struct applespi_data {
 	unsigned int			cmd_msg_cntr;
 	/* lock to protect the above parameters and flags below */
 	spinlock_t			cmd_msg_lock;
-	bool				cmd_msg_queued;
+	ktime_t				cmd_msg_queued;
 	enum applespi_evt_type		cmd_evt_type;
 
 	struct led_classdev		backlight_info;
@@ -716,7 +717,7 @@ static void applespi_msg_complete(struct applespi_data *applespi,
 		wake_up_all(&applespi->drain_complete);
 
 	if (is_write_msg) {
-		applespi->cmd_msg_queued = false;
+		applespi->cmd_msg_queued = 0;
 		applespi_send_cmd_msg(applespi);
 	}
 
@@ -758,8 +759,16 @@ static int applespi_send_cmd_msg(struct applespi_data *applespi)
 		return 0;
 
 	/* check whether send is in progress */
-	if (applespi->cmd_msg_queued)
-		return 0;
+	if (applespi->cmd_msg_queued) {
+		if (ktime_ms_delta(ktime_get(), applespi->cmd_msg_queued) < 1000)
+			return 0;
+
+		dev_warn(&applespi->spi->dev, "Command %d timed out\n",
+			 applespi->cmd_evt_type);
+
+		applespi->cmd_msg_queued = 0;
+		applespi->write_active = false;
+	}
 
 	/* set up packet */
 	memset(packet, 0, APPLESPI_PACKET_SIZE);
@@ -856,7 +865,7 @@ static int applespi_send_cmd_msg(struct applespi_data *applespi)
 		return sts;
 	}
 
-	applespi->cmd_msg_queued = true;
+	applespi->cmd_msg_queued = ktime_get_coarse();
 	applespi->write_active = true;
 
 	return 0;
@@ -1908,7 +1917,7 @@ static int __maybe_unused applespi_resume(struct device *dev)
 	applespi->drain = false;
 	applespi->have_cl_led_on = false;
 	applespi->have_bl_level = 0;
-	applespi->cmd_msg_queued = false;
+	applespi->cmd_msg_queued = 0;
 	applespi->read_active = false;
 	applespi->write_active = false;