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c=relaxed/relaxed; s=zoho; d=iav.lv; v=1; bh=+G4rf1hzJmKdD7EoOaWqne7TUKWl699YR7p6ZHK04Pg=; h=Content-Description:Content-ID:Content-Type:Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Owner:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:Resent-Sender:Resent-Cc:Resent-Date:Resent-To:Reply-To:Resent-Message-ID:Resent-From:Sender:Subject:To:Date:From:Message-Id:Reply-To:Subject:To:Cc; Received: by smtp.zoho.eu with SMTPS id 1793817481738396.6696032790776; Wed, 4 Nov 2026 19:38:01 +0100 (CET) Date: Wed, 04 Nov 2026 20:38:00 +0200 From: Igor Velkov To: Neil Armstrong Cc: iav@iav.lv, John Stultz , Thomas Gleixner , Alexandre Belloni , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Kevin Hilman , Stephen Boyd , Miroslav Lichvar , Jerome Brunet , Martin Blumenstingl , linux-rtc@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH RFC 0/3] alarmtimer: Choose the wakeup RTC per sleep state from the device tree Message-ID: <20261104-alarmtimer-rtc-neil-reply-1@iav.lv> In-Reply-To: <399668f0-e97a-438e-b761-1ea6c18d904b@linaro.org> References: <20261104-b4-alarmtimer-rtc-priority-v1-0-e996681b8086@iav.lv> <399668f0-e97a-438e-b761-1ea6c18d904b@linaro.org> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit On 11/4/26, Neil Armstrong wrote: > This sounds bulky, perhaps it would be much simpler if we just added > all the available RTCs which has RTC_FEATURE_ALARM and can wakeup ? > > Just switch from 1 single to multiple RTCs in a linked list and you're > done, no DT & bindings changes. A list it is, and v2 drops linux,alarmtimer-priority. Arming every RTC makes the coarsest one fire first: pcf8563 has no alarm seconds, so its alarm comes up to 59 s early, and an RTC with alarm_offset_max wakes earlier still. The board wakes before the timer expires, and the next alarm may come seconds later: while it is still resuming, which takes seconds with disks and PCIe, or right after it is suspended again. Drivers then go through suspend and resume at short intervals. Arming one RTC per sleep state avoids that, and which RTC wakes from which state is board knowledge, so v2 keeps linux,wakeup-states. -- Igor Velkov