From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Raul E Rangel <rrangel@chromium.org>
Cc: linux-input@vger.kernel.org, Shirish.S@amd.com,
Andy Shevchenko <andy@infradead.org>, Dan Murphy <dmurphy@ti.com>,
Darren Hart <dvhart@infradead.org>,
Jacek Anaszewski <jacek.anaszewski@gmail.com>,
"Lee, Chun-Yi" <jlee@suse.com>, Pavel Machek <pavel@ucw.cz>,
Rajat Jain <rajatja@google.com>,
Stephen Boyd <swboyd@chromium.org>,
linux-kernel@vger.kernel.org, linux-leds@vger.kernel.org,
platform-driver-x86@vger.kernel.org
Subject: Re: [PATCH v2 1/2] Input: i8042 - Prevent intermixing i8042 commands
Date: Sun, 6 Dec 2020 22:40:32 -0800 [thread overview]
Message-ID: <X83OYA0TaUszBD1y@google.com> (raw)
In-Reply-To: <20200827144112.v2.1.I6981f9a9f0c12e60f8038f3b574184f8ffc1b9b5@changeid>
Hi Raul,
On Thu, Aug 27, 2020 at 02:41:53PM -0600, Raul E Rangel wrote:
> The i8042_mutex must be held by writers of the AUX and KBD ports, as
> well as users of i8042_command. There were a lot of users of
> i8042_command that were not calling i8042_lock_chip/i8042_unlock_chip.
> This resulted in i8042_commands being issues in between PS/2
> transactions.
>
> This change moves the mutex lock into i8042_command and removes the
> burden of locking the mutex from the callers.
I think there is a benefit for allowing users issue a sequence of
commands to i8042 without interruptions, so I would prefer keeping
i8042_[un]lock_chip() in place.
Given that the issue you were observing was caused by i8042_port_close()
interfering with probing, maybe we could do something like this:
diff --git a/drivers/input/serio/i8042.c b/drivers/input/serio/i8042.c
index abae23af0791..aff871001eda 100644
--- a/drivers/input/serio/i8042.c
+++ b/drivers/input/serio/i8042.c
@@ -344,6 +344,8 @@ int i8042_command(unsigned char *param, int command)
unsigned long flags;
int retval;
+ lockdep_assert_held(&i8042_mutex);
+
if (!i8042_present)
return -1;
@@ -364,6 +366,8 @@ static int i8042_kbd_write(struct serio *port, unsigned char c)
unsigned long flags;
int retval = 0;
+ lockdep_assert_held(&i8042_mutex);
+
spin_lock_irqsave(&i8042_lock, flags);
if (!(retval = i8042_wait_write())) {
@@ -411,6 +415,8 @@ static void i8042_port_close(struct serio *serio)
port_name = "KBD";
}
+ i8042_lock_chip();
+
i8042_ctr &= ~irq_bit;
if (i8042_command(&i8042_ctr, I8042_CMD_CTL_WCTR))
pr_warn("Can't write CTR while closing %s port\n", port_name);
@@ -422,6 +428,8 @@ static void i8042_port_close(struct serio *serio)
if (i8042_command(&i8042_ctr, I8042_CMD_CTL_WCTR))
pr_err("Can't reactivate %s port\n", port_name);
+ i8042_unlock_chip();
+
/*
* See if there is any data appeared while we were messing with
* port state.
Thanks.
--
Dmitry
prev parent reply other threads:[~2020-12-07 6:41 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-27 20:41 [PATCH v2 1/2] Input: i8042 - Prevent intermixing i8042 commands Raul E Rangel
2020-10-28 20:35 ` Hans de Goede
2020-12-07 6:40 ` Dmitry Torokhov [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=X83OYA0TaUszBD1y@google.com \
--to=dmitry.torokhov@gmail.com \
--cc=Shirish.S@amd.com \
--cc=andy@infradead.org \
--cc=dmurphy@ti.com \
--cc=dvhart@infradead.org \
--cc=jacek.anaszewski@gmail.com \
--cc=jlee@suse.com \
--cc=linux-input@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-leds@vger.kernel.org \
--cc=pavel@ucw.cz \
--cc=platform-driver-x86@vger.kernel.org \
--cc=rajatja@google.com \
--cc=rrangel@chromium.org \
--cc=swboyd@chromium.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).