Re: [PATCH] media/rc: compile rc-cec.c into rc-core
From: Sean Young <sean@mess.org>
Date: 2021-02-20 10:59:34
Hi Hans, Thank you for writing this patch. On Thu, Feb 18, 2021 at 05:13:08PM +0100, Hans Verkuil wrote:
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The rc-cec keymap is unusual in that it can't be built as a module, instead it is registered directly in rc-main.c if CONFIG_MEDIA_CEC_RC is set. This is because it can be called from drm_dp_cec_set_edid() via cec_register_adapter() in an asynchronous context, and it is not allowed to use request_module() to load rc-cec.ko in that case. Trying to do so results in a 'WARN_ON_ONCE(wait && current_is_async())'. Since this keymap is only used if CONFIG_MEDIA_CEC_RC is set, we just compile this keymap into the rc-core module and never as a separate module. Signed-off-by: Hans Verkuil <redacted> Fixes: 2c6d1fffa1d9 (drm: add support for DisplayPort CEC-Tunneling-over-AUX) Reported-by: Hans de Goede <redacted> --- Sean, I tested this both with RC_CORE=y and =m. It looks reasonably clean to me, but I am not sure if this affects v4l-utils as well. Let me know what you think. Regards, Hans ---diff --git a/drivers/media/rc/Makefile b/drivers/media/rc/Makefile index 5bb2932ab119..ff6a8fc4c38e 100644 --- a/drivers/media/rc/Makefile +++ b/drivers/media/rc/Makefile@@ -5,6 +5,7 @@ obj-y += keymaps/ obj-$(CONFIG_RC_CORE) += rc-core.o rc-core-y := rc-main.o rc-ir-raw.o rc-core-$(CONFIG_LIRC) += lirc_dev.o +rc-core-$(CONFIG_MEDIA_CEC_RC) += keymaps/rc-cec.o rc-core-$(CONFIG_BPF_LIRC_MODE2) += bpf-lirc.o obj-$(CONFIG_IR_NEC_DECODER) += ir-nec-decoder.o obj-$(CONFIG_IR_RC5_DECODER) += ir-rc5-decoder.odiff --git a/drivers/media/rc/keymaps/Makefile b/drivers/media/rc/keymaps/Makefile index b252a1d2ebd6..cc6662e1903f 100644 --- a/drivers/media/rc/keymaps/Makefile +++ b/drivers/media/rc/keymaps/Makefile@@ -21,7 +21,6 @@ obj-$(CONFIG_RC_MAP) += rc-adstech-dvb-t-pci.o \ rc-behold.o \ rc-behold-columbus.o \ rc-budget-ci-old.o \ - rc-cec.o \ rc-cinergy-1400.o \ rc-cinergy.o \ rc-d680-dmb.o \
This is a great idea. If rc-core is built as a module, the cec keymap is included in the module, and if cec-rc is not enabled then it is not built at all.
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diff --git a/drivers/media/rc/keymaps/rc-cec.c b/drivers/media/rc/keymaps/rc-cec.c index 3e3bd11092b4..068e22aeac8c 100644 --- a/drivers/media/rc/keymaps/rc-cec.c +++ b/drivers/media/rc/keymaps/rc-cec.c@@ -1,5 +1,15 @@ // SPDX-License-Identifier: GPL-2.0-or-later /* Keytable for the CEC remote control + * + * This keymap is unusual in that it can't be built as a module, + * instead it is registered directly in rc-main.c if CONFIG_MEDIA_CEC_RC + * is set. This is because it can be called from drm_dp_cec_set_edid() via + * cec_register_adapter() in an asynchronous context, and it is not + * allowed to use request_module() to load rc-cec.ko in that case. + * + * Since this keymap is only used if CONFIG_MEDIA_CEC_RC is set, we + * just compile this keymap into the rc-core module and never as a + * separate module. * * Copyright (c) 2015 by Kamil Debski */@@ -152,7 +162,7 @@ static struct rc_map_table cec[] = { /* 0x77-0xff: Reserved */ }; -static struct rc_map_list cec_map = { +struct rc_map_list cec_map = { .map = { .scan = cec, .size = ARRAY_SIZE(cec),@@ -160,19 +170,3 @@ static struct rc_map_list cec_map = { .name = RC_MAP_CEC, } }; - -static int __init init_rc_map_cec(void) -{ - return rc_map_register(&cec_map); -} - -static void __exit exit_rc_map_cec(void) -{ - rc_map_unregister(&cec_map); -} - -module_init(init_rc_map_cec); -module_exit(exit_rc_map_cec); - -MODULE_LICENSE("GPL"); -MODULE_AUTHOR("Kamil Debski");diff --git a/drivers/media/rc/rc-main.c b/drivers/media/rc/rc-main.c index 1fd62c1dac76..4768b1e9ffd1 100644 --- a/drivers/media/rc/rc-main.c +++ b/drivers/media/rc/rc-main.c@@ -163,6 +163,10 @@ static struct rc_map_list empty_map = { } }; +#ifdef CONFIG_MEDIA_CEC_RC +extern struct rc_map_list cec_map; +#endif + /** * scancode_to_u64() - converts scancode in &struct input_keymap_entry * @ke: keymap entry containing scancode to be converted.@@ -2069,6 +2073,9 @@ static int __init rc_core_init(void) led_trigger_register_simple("rc-feedback", &led_feedback); rc_map_register(&empty_map); +#ifdef CONFIG_MEDIA_CEC_RC + rc_map_register(&cec_map); +#endif return 0; }@@ -2078,6 +2085,9 @@ static void __exit rc_core_exit(void) lirc_dev_exit(); class_unregister(&rc_class); led_trigger_unregister_simple(led_feedback); +#ifdef CONFIG_MEDIA_CEC_RC + rc_map_register(&cec_map); +#endif rc_map_unregister(&empty_map); }
Now I'm confused. Do we need these changes at all? I've experimented a little bit (without the right hardware), and as far as I can make out, just the changes to the Kconfig/Makefile should be enough. Thanks, Sean