From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
Cc: linux-kernel@vger.kernel.org, linux-input@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jiri Slaby <jslaby@suse.com>,
kernel@collabora.com
Subject: Re: [PATCH] tty/sysrq: Add alternative SysRq key
Date: Wed, 8 Jul 2020 22:05:38 -0700 [thread overview]
Message-ID: <20200709050538.GG3273837@dtor-ws> (raw)
In-Reply-To: <20200619162819.715-1-andrzej.p@collabora.com>
Hi Andrzej,
On Fri, Jun 19, 2020 at 06:28:19PM +0200, Andrzej Pietrasiewicz wrote:
> There exist machines which don't have SysRq key at all, e.g. chromebooks.
>
> This patch allows configuring an alternative key to act as SysRq. Devices
> which declare KEY_SYSRQ in their 'keybit' bitmap continue using KEY_SYSRQ,
> but other devices use the alternative SysRq key instead, by default F10.
> Which key is actually used can be modified with sysrq's module parameter.
I guess you will be removing KEY_SYSRQ form all Chrome OS internal AT
keyboards and external USB keyboard with Chrome OS layouts as well? Via
udev keymap? I suppose this could work... Or have a per device setting
as we allocate a separate handle for each input device attached to the
SysRq handler.
>
> Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
> ---
> drivers/tty/sysrq.c | 28 +++++++++++++++++++++++++---
> 1 file changed, 25 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
> index 0dc3878794fd..e1d271c84746 100644
> --- a/drivers/tty/sysrq.c
> +++ b/drivers/tty/sysrq.c
> @@ -604,6 +604,7 @@ EXPORT_SYMBOL(handle_sysrq);
>
> #ifdef CONFIG_INPUT
> static int sysrq_reset_downtime_ms;
> +static unsigned short alternative_sysrq_key = KEY_F10;
>
> /* Simple translation table for the SysRq keys */
> static const unsigned char sysrq_xlate[KEY_CNT] =
> @@ -621,6 +622,7 @@ struct sysrq_state {
> unsigned long key_down[BITS_TO_LONGS(KEY_CNT)];
> unsigned int alt;
> unsigned int alt_use;
> + unsigned short sysrq_key;
> bool active;
> bool need_reinject;
> bool reinjecting;
> @@ -770,10 +772,10 @@ static void sysrq_reinject_alt_sysrq(struct work_struct *work)
>
> /* Simulate press and release of Alt + SysRq */
> input_inject_event(handle, EV_KEY, alt_code, 1);
> - input_inject_event(handle, EV_KEY, KEY_SYSRQ, 1);
> + input_inject_event(handle, EV_KEY, sysrq->sysrq_key, 1);
> input_inject_event(handle, EV_SYN, SYN_REPORT, 1);
>
> - input_inject_event(handle, EV_KEY, KEY_SYSRQ, 0);
> + input_inject_event(handle, EV_KEY, sysrq->sysrq_key, 0);
> input_inject_event(handle, EV_KEY, alt_code, 0);
> input_inject_event(handle, EV_SYN, SYN_REPORT, 1);
>
> @@ -805,6 +807,7 @@ static bool sysrq_handle_keypress(struct sysrq_state *sysrq,
> }
> break;
>
> +key_sysrq:
> case KEY_SYSRQ:
> if (value == 1 && sysrq->alt != KEY_RESERVED) {
> sysrq->active = true;
> @@ -825,11 +828,15 @@ static bool sysrq_handle_keypress(struct sysrq_state *sysrq,
> * triggering print screen function.
> */
> if (sysrq->active)
> - clear_bit(KEY_SYSRQ, sysrq->handle.dev->key);
> + clear_bit(sysrq->sysrq_key, sysrq->handle.dev->key);
>
> break;
>
> default:
> + /* handle non-default sysrq key */
> + if (code == sysrq->sysrq_key)
> + goto key_sysrq;
> +
> if (sysrq->active && value && value != 2) {
> sysrq->need_reinject = false;
> __handle_sysrq(sysrq_xlate[code], true);
> @@ -924,6 +931,14 @@ static int sysrq_connect(struct input_handler *handler,
> sysrq->handle.private = sysrq;
> timer_setup(&sysrq->keyreset_timer, sysrq_do_reset, 0);
>
> + if (test_bit(KEY_SYSRQ, dev->keybit)) {
> + sysrq->sysrq_key = KEY_SYSRQ;
> + pr_info("%s: using default sysrq key [%x]\n", dev->name, KEY_SYSRQ);
> + } else {
> + sysrq->sysrq_key = alternative_sysrq_key;
> + pr_info("%s: Using alternative sysrq key: [%x]\n", dev->name, sysrq->sysrq_key);
> + }
This is way too noisy IMO.
> +
> error = input_register_handle(&sysrq->handle);
> if (error) {
> pr_err("Failed to register input sysrq handler, error %d\n",
> @@ -1032,6 +1047,13 @@ module_param_array_named(reset_seq, sysrq_reset_seq, sysrq_reset_seq,
>
> module_param_named(sysrq_downtime_ms, sysrq_reset_downtime_ms, int, 0644);
>
> +module_param(alternative_sysrq_key, ushort, 0644);
> +MODULE_PARM_DESC(alternative_sysrq_key,
> + "Alternative SysRq key for input devices that don't have SysRq key. F10 by default.\n"
> + "Example\n"
> + "Using F9 as SysRq:\n"
> + "sysrq.alternative_sysrq_key=0x43\n");
> +
> #else
>
> static inline void sysrq_register_handler(void)
>
> base-commit: 3d77e6a8804abcc0504c904bd6e5cdf3a5cf8162
> --
> 2.17.1
>
--
Dmitry
next prev parent reply other threads:[~2020-07-09 5:05 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-11 13:59 [PATCH 0/6] Magic SysRq extensions Andrzej Pietrasiewicz
2020-05-11 13:59 ` [PATCH 1/6] tty/sysrq: Remove linux,sysrq-reset-seq Andrzej Pietrasiewicz
2020-05-11 17:58 ` Dmitry Torokhov
2020-05-12 9:21 ` Andrzej Pietrasiewicz
2020-05-11 13:59 ` [PATCH 2/6] dt-bindings: input: Remove linux,sysrq-reset-seq binding Andrzej Pietrasiewicz
2020-05-11 13:59 ` [PATCH 3/6] tty/sysrq: Allow configurable SysRq key Andrzej Pietrasiewicz
2020-05-11 16:18 ` Greg Kroah-Hartman
2020-05-11 18:01 ` Dmitry Torokhov
2020-05-12 9:46 ` Andrzej Pietrasiewicz
2020-06-19 16:28 ` [PATCH] tty/sysrq: Add alternative " Andrzej Pietrasiewicz
2020-06-21 21:21 ` Pavel Machek
2020-06-26 11:07 ` Andrzej Pietrasiewicz
2020-06-22 6:24 ` Jiri Slaby
2020-06-26 11:51 ` Andrzej Pietrasiewicz
2020-07-09 5:05 ` Dmitry Torokhov [this message]
2020-07-09 8:15 ` Andrzej Pietrasiewicz
2020-05-11 13:59 ` [PATCH 4/6] tty/sysrq: Extend the sysrq_key_table to cover capital letters Andrzej Pietrasiewicz
2020-05-11 13:59 ` [PATCH 5/6] tty/sysrq: Add configurable handler to signal a process Andrzej Pietrasiewicz
2020-05-11 16:20 ` Greg Kroah-Hartman
2020-05-14 9:06 ` kbuild test robot
2020-05-11 13:59 ` [PATCH 6/6] tty/sysrq: Add configurable handler to execute a compound action Andrzej Pietrasiewicz
2020-05-11 16:21 ` Greg Kroah-Hartman
2020-05-11 18:29 ` Dmitry Torokhov
2020-05-12 9:15 ` Andrzej Pietrasiewicz
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