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 80EDE1487E1; Thu, 13 Jun 2024 11:56:16 +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=1718279776; cv=none; b=ZkD2OV8F6eMILQtER7KQLOTYD6SJRyN4fGfDtw2KzYTDehHzs7eSFvP7MEuKUONyrXM4T/r0xJStsMqfuTNwlCYTrMBCWN1w5Y74X0+ohFIEoT/sBVwW3g/mxTe+jF3OqvYUSxIMTL78a2DaFf8lUdW+YN80TftRi9BuF95iLTI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718279776; c=relaxed/simple; bh=FNXo9Ua1yH676sOT3+X5ukYinyTQpgMlL5qDC+fvWa0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=t+iVcgqFRORTQ00t/oAZwBvOcnVt1arBWV8i32udtTnDYDlvj+HKaayBH+Jwzp+3QEW3e3K1lLxgQg0pMP1gYwgR05AiXR7cknXUMjD7Es2DYC3ewTxh3OxrTHcLmzSsUbaygIJQ62pfKO1LSqP3sE2CT3G/cFo/uQ46L/V1qSs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=xDl5y/Hg; 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="xDl5y/Hg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 07CECC2BBFC; Thu, 13 Jun 2024 11:56:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1718279776; bh=FNXo9Ua1yH676sOT3+X5ukYinyTQpgMlL5qDC+fvWa0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xDl5y/HgpPxsyMZQRlzvLVaKL+aXrJXGi9Xvo9CK7WPSFoeEXdoB/+3fPTTLMe5LA 8i2O6v6ho6aZSqOdIN7Bp4Hgg4CLNNy6l2imUQWiXY84OZFJbhCPDSsTDN9JGNDfNB DyN/NSogdxFRzOQC5n3Ri9VCqofG3Q4Hfdo/t45g= 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 5.4 033/202] scsi: ufs: core: Perform read back after disabling UIC_COMMAND_COMPL Date: Thu, 13 Jun 2024 13:32:11 +0200 Message-ID: <20240613113229.051814029@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240613113227.759341286@linuxfoundation.org> References: <20240613113227.759341286@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-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 ea6148ee27835..e54a08f96a500 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -3731,7 +3731,7 @@ 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