From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7EA521AD3FA; Mon, 23 Jun 2025 21:57:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750715839; cv=none; b=PtsZAJyIhZfXqyTkzoOlIbXRqC+RA2BBKr4Q3NLVdpLE07LpbUwqLQxguW10S7oCjLG8taR59ltoqfOq5gKol14v7YSLXcEx27tddJHY5luZ+8vA3hNDj+KdlOhk12LziySmPLxsOPTcURJdUYSPKZtyq7XNJ8Dll2/uzlgH2Cw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750715839; c=relaxed/simple; bh=rFX8YJEGFRruqKJiYJp48tsmFxPoOtCJUvJCabDMUpc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Exoezjbsy8nfioxedXsnRN6vP+IFKWhsBsWI8hGiwA+omPnD/TJPrOuC6R9bojYaV5pZZiJNAfd1MM6zlvJ6JDHdHSc5B7XFYq+gS0sebchrlNVF+O1nmsOq3aFCTFMtx6PckOUZEnhcQ/C9VpcxMcB7ISSsDahgJjh/vvc+lRc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=i/4FSY5y; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="i/4FSY5y" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CC8E2C4CEEA; Mon, 23 Jun 2025 21:57:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1750715839; bh=rFX8YJEGFRruqKJiYJp48tsmFxPoOtCJUvJCabDMUpc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=i/4FSY5ySD0LWCUHOqKu73JyVwUkoI/DsHYuGB9foFnqb8OGfJw+/IM4WyH4UiWet sNm1oWOaApLj3STn/Svqv92RV63SUuCNQEkbYF8ADiVXKg+oUwh6hqS4TY4Xu5z1+h SLGpq337wwXKZdwKQfdtB8Hje10n5Vlg6O74h+0Y= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Tan En De , Jarkko Nikula , Andi Shyti , Sasha Levin Subject: [PATCH 5.15 307/411] i2c: designware: Invoke runtime suspend on quick slave re-registration Date: Mon, 23 Jun 2025 15:07:31 +0200 Message-ID: <20250623130641.372446609@linuxfoundation.org> X-Mailer: git-send-email 2.50.0 In-Reply-To: <20250623130632.993849527@linuxfoundation.org> References: <20250623130632.993849527@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tan En De [ Upstream commit 2fe2b969d911a09abcd6a47401a3c66c38a310e6 ] Replaced pm_runtime_put() with pm_runtime_put_sync_suspend() to ensure the runtime suspend is invoked immediately when unregistering a slave. This prevents a race condition where suspend was skipped when unregistering and registering slave in quick succession. For example, consider the rapid sequence of `delete_device -> new_device -> delete_device -> new_device`. In this sequence, it is observed that the dw_i2c_plat_runtime_suspend() might not be invoked after `delete_device` operation. This is because after `delete_device` operation, when the pm_runtime_put() is about to trigger suspend, the following `new_device` operation might race and cancel the suspend. If that happens, during the `new_device` operation, dw_i2c_plat_runtime_resume() is skipped (since there was no suspend), which means `i_dev->init()`, i.e. i2c_dw_init_slave(), is skipped. Since i2c_dw_init_slave() is skipped, i2c_dw_configure_fifo_slave() is skipped too, which leaves `DW_IC_INTR_MASK` unconfigured. If we inspect the interrupt mask register using devmem, it will show as zero. Example shell script to reproduce the issue: ``` #!/bin/sh SLAVE_LADDR=0x1010 SLAVE_BUS=13 NEW_DEVICE=/sys/bus/i2c/devices/i2c-$SLAVE_BUS/new_device DELETE_DEVICE=/sys/bus/i2c/devices/i2c-$SLAVE_BUS/delete_device # Create initial device echo slave-24c02 $SLAVE_LADDR > $NEW_DEVICE sleep 2 # Rapid sequence of # delete_device -> new_device -> delete_device -> new_device echo $SLAVE_LADDR > $DELETE_DEVICE echo slave-24c02 $SLAVE_LADDR > $NEW_DEVICE echo $SLAVE_LADDR > $DELETE_DEVICE echo slave-24c02 $SLAVE_LADDR > $NEW_DEVICE # Using devmem to inspect IC_INTR_MASK will show as zero ``` Signed-off-by: Tan En De Acked-by: Jarkko Nikula Link: https://lore.kernel.org/r/20250412023303.378600-1-ende.tan@starfivetech.com Signed-off-by: Andi Shyti Signed-off-by: Sasha Levin --- drivers/i2c/busses/i2c-designware-slave.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/i2c/busses/i2c-designware-slave.c b/drivers/i2c/busses/i2c-designware-slave.c index 5b54a9b9ed1a3..09b8ccc040c6e 100644 --- a/drivers/i2c/busses/i2c-designware-slave.c +++ b/drivers/i2c/busses/i2c-designware-slave.c @@ -97,7 +97,7 @@ static int i2c_dw_unreg_slave(struct i2c_client *slave) dev->disable(dev); synchronize_irq(dev->irq); dev->slave = NULL; - pm_runtime_put(dev->dev); + pm_runtime_put_sync_suspend(dev->dev); return 0; } -- 2.39.5