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 B92FC1428FC; Thu, 13 Jun 2024 11:38:09 +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=1718278689; cv=none; b=r9AaKoClJXjwxUGPUq8gEAsy+FC5JoUYZnmShh72sAnSjGt+stntHjRORuVtN5SvmkQ/TM6gi64odyAQejFO44fmm83L21e5JXDempt5FT3IA3SYSF5hJJUsAVEz08rIcOrGINNeErbjPFTH7P2ly+m8OxnLvTH/hTScA2WqfEI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718278689; c=relaxed/simple; bh=Qfnc6EQZ+nDHbGwr88XMpEpYBC03wdvqZdkpYZ595nY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FyjYdFF7y62MwUsiWNo8J3KJTlv+2ojfzGUt7EYBsttQOcoqkVp9TapD08RoUk42wdjwrlu8aasDdcDp1gkno3wirTpFI+LJnui+4k9kfXH9e5x6KHGqjTYtcRM0Nolit+ZyQ6YHvx1zYDQKRXbN15ThVa1te538DCgeiCxO0b4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=0lFU+93Y; 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="0lFU+93Y" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 436ABC2BBFC; Thu, 13 Jun 2024 11:38:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1718278689; bh=Qfnc6EQZ+nDHbGwr88XMpEpYBC03wdvqZdkpYZ595nY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0lFU+93YvtH8+iYZ8YhAtQOTZGbkp8DTjh3i/fgIll8IcOy9XwmngEaL5P80Dm8Xs gMBVOqrUWlFSnC6W8IT8s1iOygBzVhN/U/sDojAzcWxMR7ILl+ahnh5DsC/YkhRK0p i+hOqt1S/QbV6nVQ7qlZwCHRFeH1wWFTXmCZrg1U= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Bart Van Assche , Can Guo , Manivannan Sadhasivam , Andrew Halaney , "Martin K. Petersen" , Sasha Levin Subject: [PATCH 4.19 036/213] scsi: ufs: core: Perform read back after disabling UIC_COMMAND_COMPL Date: Thu, 13 Jun 2024 13:31:24 +0200 Message-ID: <20240613113229.392009247@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240613113227.969123070@linuxfoundation.org> References: <20240613113227.969123070@linuxfoundation.org> User-Agent: quilt/0.67 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 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Andrew Halaney [ Upstream commit 4bf3855497b60765ca03b983d064b25e99b97657 ] Currently, the UIC_COMMAND_COMPL interrupt is disabled and a wmb() is used to complete the register write before any following writes. wmb() ensures the writes complete in that order, but completion doesn't mean that it isn't stored in a buffer somewhere. The recommendation for ensuring this bit has taken effect on the device is to perform a read back to force it to make it all the way to the device. This is documented in device-io.rst and a talk by Will Deacon on this can be seen over here: https://youtu.be/i6DayghhA8Q?si=MiyxB5cKJXSaoc01&t=1678 Let's do that to ensure the bit hits the device. Because the wmb()'s purpose wasn't to add extra ordering (on top of the ordering guaranteed by writel()/readl()), it can safely be removed. Fixes: d75f7fe495cf ("scsi: ufs: reduce the interrupts for power mode change requests") Reviewed-by: Bart Van Assche Reviewed-by: Can Guo Reviewed-by: Manivannan Sadhasivam Signed-off-by: Andrew Halaney Link: https://lore.kernel.org/r/20240329-ufs-reset-ensure-effect-before-delay-v5-9-181252004586@redhat.com Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin --- drivers/scsi/ufs/ufshcd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index b6129b822ed18..5426bfe522d2d 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -3754,7 +3754,7 @@ static int ufshcd_uic_pwr_ctrl(struct ufs_hba *hba, struct uic_command *cmd) * Make sure UIC command completion interrupt is disabled before * issuing UIC command. */ - wmb(); + ufshcd_readl(hba, REG_INTERRUPT_ENABLE); reenable_intr = true; } ret = __ufshcd_send_uic_cmd(hba, cmd, false); -- 2.43.0