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 F40B91BEF8A for ; Fri, 21 Feb 2025 01:54:27 +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=1740102868; cv=none; b=DdYm9l1K4a1ORGMlJDd/SYdGy647nrlZP9gkCrppXSw+JXiwPcE+m/PNTKDekVwS7zN2jiv0zYKkGUwwBbKG6teZFJFOMhIxJWSgVellCiQAULkPo5BPpU4qLbH27P+jVZzO4FV//CE05MMd/jeeWqgZagjDJ7JPIkRGIgOhLcw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740102868; c=relaxed/simple; bh=fufAntR8nLPFeqgMuXx46QWPVLjoi5MaKAju54ZEPB4=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=H72A46jj1oUJEER08Q93guG60lebwSwkuNZcJukeLBCYTCRJM0RusTIlk91VGG1+zsba2aj7LLBy3RZ/P/0vRsh5hoSWjxQBIyBIps54VDM+lR2ZYgLCjg8cWL1nlFTOw8Ng5UHNplSCjpH4aBUqXj4zC0uHpBGa0NGXnwo/I80= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Y+FrJBvg; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Y+FrJBvg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5DC47C4CED1; Fri, 21 Feb 2025 01:54:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1740102867; bh=fufAntR8nLPFeqgMuXx46QWPVLjoi5MaKAju54ZEPB4=; h=From:To:Cc:Subject:Date:From; b=Y+FrJBvg7pvSgHdK6BoIFEgikJyIHL5a2kzG6uYF658SELB5cbcFdYbPwUCimt+ss b1f+Bc/q2YcRyENygI7ah/l021d4UYBurS7m0Rdlgm4XLh7uxLIoW+M5qlCIUbYY2W gCUv2ViUuyeov48cAlP5LnPBBcgNtY0s6TSlT5EZXBUeDPSTj/ikYFsI9mAuW5nbLr 8nP5YK6ZeuREoMpx2DfMnKLIdIrVJr++y3RRYdJi8uGwUpd/x1fUXox7TYov31BqE1 4XCpDR86jF+J6ssDlJ6k3AUeHCA9BNxE05T/ZG6+4fz4oA5Oozm9xg2SDnwpnEkryU mdLoclGJ2Ep9Q== From: Niklas Cassel To: Damien Le Moal , Niklas Cassel Cc: Philip Pemberton , linux-ide@vger.kernel.org Subject: [PATCH] ata: libata-eh: Do not use ATAPI DMA for a device limited to PIO mode Date: Fri, 21 Feb 2025 02:54:23 +0100 Message-ID: <20250221015422.20687-2-cassel@kernel.org> X-Mailer: git-send-email 2.48.1 Precedence: bulk X-Mailing-List: linux-ide@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1721; i=cassel@kernel.org; h=from:subject; bh=fufAntR8nLPFeqgMuXx46QWPVLjoi5MaKAju54ZEPB4=; b=owGbwMvMwCV2MsVw8cxjvkWMp9WSGNK33zn3JG6+wHv3r6/snAIzVi99se/j6WeiC90yvGI0C nldZjHu6ShlYRDjYpAVU2Tx/eGyv7jbfcpxxTs2MHNYmUCGMHBxCsBEuiwZ/sembl6/aeORCbxT FnX8rZZZ+le9zOtu1w/7swGhrcH7H3kwMnw03Nz55pPRzDMTpivO5D5wZq9CsVJJS8gTDU72RJ8 D1lwA X-Developer-Key: i=cassel@kernel.org; a=openpgp; fpr=5ADE635C0E631CBBD5BE065A352FE6582ED9B5DA Content-Transfer-Encoding: 8bit atapi_eh_request_sense() currently uses ATAPI DMA if the SATA controller has ATA_FLAG_PIO_DMA (PIO cmds via DMA) set. However, ATA_FLAG_PIO_DMA is a flag that can be set by a low-level driver on a port at initialization time, before any devices are scanned. If a controller detects a connected device that only supports PIO, we set the flag ATA_DFLAG_PIO. Modify atapi_eh_request_sense() to not use ATAPI DMA if the connected device only supports PIO. Reported-by: Philip Pemberton Closes: https://lore.kernel.org/linux-ide/c6722ee8-5e21-4169-af59-cbbae9edc02f@philpem.me.uk/ Signed-off-by: Niklas Cassel --- drivers/ata/libata-eh.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c index 3b303d4ae37a..16cd676eae1f 100644 --- a/drivers/ata/libata-eh.c +++ b/drivers/ata/libata-eh.c @@ -1542,8 +1542,15 @@ unsigned int atapi_eh_request_sense(struct ata_device *dev, tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE; tf.command = ATA_CMD_PACKET; - /* is it pointless to prefer PIO for "safety reasons"? */ - if (ap->flags & ATA_FLAG_PIO_DMA) { + /* + * Do not use DMA if the connected device only supports PIO, even if the + * port prefers PIO commands via DMA. + * + * Ideally, we should call atapi_check_dma() to check if it is safe for + * the LLD to use DMA for REQUEST_SENSE, but we don't have a qc. + * Since we can't check the command, perhaps we should only use pio? + */ + if ((ap->flags & ATA_FLAG_PIO_DMA) && !(dev->flags & ATA_DFLAG_PIO)) { tf.protocol = ATAPI_PROT_DMA; tf.feature |= ATAPI_PKT_DMA; } else { -- 2.48.1