From patchwork Fri Nov 15 20:58:31 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Rafael J. 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Wysocki" To: Linux PM , Peter Zijlstra Cc: LKML , x86 Maintainers , Patryk Wlazlyn , "Gautham R. Shenoy" , Artem Bityutskiy , Mario Limonciello , Linux ACPI Subject: [PATCH v2 1/2] cpuidle: Do not return from cpuidle_play_dead() on callback failures Date: Fri, 15 Nov 2024 21:58:31 +0100 Message-ID: <3318440.aeNJFYEL58@rjwysocki.net> In-Reply-To: <13636465.uLZWGnKmhe@rjwysocki.net> References: <13636465.uLZWGnKmhe@rjwysocki.net> Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CLIENT-IP: 195.136.19.94 X-CLIENT-HOSTNAME: 195.136.19.94 X-VADE-SPAMSTATE: clean X-VADE-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgeefuddrvdeggddugeduucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecujffqoffgrffnpdggtffipffknecuuegrihhlohhuthemucduhedtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenucfjughrpefhvfevufffkfgjfhgggfgtsehtufertddttdejnecuhfhrohhmpedftfgrfhgrvghlucflrdcuhgihshhotghkihdfuceorhhjfiesrhhjfiihshhotghkihdrnhgvtheqnecuggftrfgrthhtvghrnhepvdffueeitdfgvddtudegueejtdffteetgeefkeffvdeftddttdeuhfegfedvjefhnecukfhppeduleehrddufeeirdduledrleegnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehinhgvthepudelhedrudefiedrudelrdelgedphhgvlhhopehkrhgvrggthhgvrhdrlhhotggrlhhnvghtpdhmrghilhhfrhhomheprhhjfiesrhhjfiihshhotghkihdrnhgvthdpnhgspghrtghpthhtohepledprhgtphhtthhopehlihhnuhigqdhpmhesvhhgvghrrdhkvghrnhgvlhdrohhrghdprhgtphhtthhopehpvghtvghriiesihhnfhhrrgguvggrugdrohhrghdprhgtphhtthhopehlihhnuhigqdhkvghrnhgvlhesvhhgvghrrdhkvghrnhgvlhdrohhrghdprhgtphhtthhopeigkeeisehkvghrnhgvlhdrohhrghdprhgtphhtthhopehprghtrhihkhdrfihlrgiilhihnheslhhinhhugidrihhnthgvlhdrtghomhdprhgtphh X-DCC--Metrics: v370.home.net.pl 0; Body=9 Fuz1=9 Fuz2=9 From: Rafael J. Wysocki If the :enter_dead() idle state callback fails for a certain state, there may be still a shallower state for which it will work. Because the only caller of cpuidle_play_dead(), native_play_dead(), falls back to hlt_play_dead() if it returns an error, it should better try all of the idle states for which :enter_dead() is present before failing, so change it accordingly. Also notice that the :enter_dead() state callback is not expected to return on success (the CPU should be "dead" then), so make cpuidle_play_dead() ignore its return value. Signed-off-by: Rafael J. Wysocki Reviewed-by: Mario Limonciello Tested-by: Mario Limonciello # 6.12-rc7 Reviewed-by: Gautham R. Shenoy --- v1 -> v2: * Make cpuidle_play_dead() never return 0. * Add tags from Mario (I have added them because the change of the patch should not make a practical difference, but if you want them to be dropped, please let me know). --- drivers/cpuidle/cpuidle.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) Index: linux-pm/drivers/cpuidle/cpuidle.c =================================================================== --- linux-pm.orig/drivers/cpuidle/cpuidle.c +++ linux-pm/drivers/cpuidle/cpuidle.c @@ -69,11 +69,15 @@ int cpuidle_play_dead(void) if (!drv) return -ENODEV; - /* Find lowest-power state that supports long-term idle */ - for (i = drv->state_count - 1; i >= 0; i--) + for (i = drv->state_count - 1; i >= 0; i--) { if (drv->states[i].enter_dead) - return drv->states[i].enter_dead(dev, i); + drv->states[i].enter_dead(dev, i); + } + /* + * If :enter_dead() is successful, it will never return, so reaching + * here means that all of them failed above or were not present. + */ return -ENODEV; }