From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alan Subject: [PATCH] libata-core: Fix simplex handling Date: Thu, 1 Mar 2007 17:36:46 +0000 Message-ID: <20070301173646.4138981b@lxorguk.ukuu.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from outpipe-village-512-1.bc.nu ([81.2.110.250]:53459 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S965337AbXCAQdM (ORCPT ); Thu, 1 Mar 2007 11:33:12 -0500 Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, akpm@osdl.org, torvalds@osdl.org, jgarzik@pobox.com The initial simplex handling code is fooled if you suspend and resume. This also causes problems with some single channel controllers which claim to be simplex. The fix is fairly simple, instead of keeping a flag to remember if we gave away the simplex channel we remember the actual owner. As the owner is always part of the host_set we don't even need a refcount. Knowing the owner also means we can reassign simplex DMA channels in future hotplug code etc if we need to Signed-off-by: Alan Cox (and a signed-off for the patch I sent before while I remember) diff -u --new-file --recursive --exclude-from /usr/src/exclude linux.vanilla-2.6.21-rc2/drivers/ata/libata-core.c linux-2.6.21-rc2/drivers/ata/libata-core.c --- linux.vanilla-2.6.21-rc2/drivers/ata/libata-core.c 2007-03-01 13:36:03.000000000 +0000 +++ linux-2.6.21-rc2/drivers/ata/libata-core.c 2007-03-01 15:49:21.853448880 +0000 @@ -2556,12 +2622,11 @@ * host channels are not permitted to do so. */ if (used_dma && (ap->host->flags & ATA_HOST_SIMPLEX)) - ap->host->simplex_claimed = 1; + ap->host->simplex_claimed = ap; /* step5: chip specific finalisation */ if (ap->ops->post_set_mode) ap->ops->post_set_mode(ap); - out: if (rc) *r_failed_dev = dev; @@ -3442,7 +3507,7 @@ "device is on DMA blacklist, disabling DMA\n"); } - if ((host->flags & ATA_HOST_SIMPLEX) && host->simplex_claimed) { + if ((host->flags & ATA_HOST_SIMPLEX) && host->simplex_claimed != ap) { xfer_mask &= ~(ATA_MASK_MWDMA | ATA_MASK_UDMA); ata_dev_printk(dev, KERN_WARNING, "simplex DMA is claimed by " "other device, disabling DMA\n"); diff -u --new-file --recursive --exclude-from /usr/src/exclude linux.vanilla-2.6.21-rc2/include/linux/libata.h linux-2.6.21-rc2/include/linux/libata.h --- linux.vanilla-2.6.21-rc2/include/linux/libata.h 2007-03-01 13:36:13.000000000 +0000 +++ linux-2.6.21-rc2/include/linux/libata.h 2007-03-01 14:27:53.363612296 +0000 @@ -403,8 +403,7 @@ void *private_data; const struct ata_port_operations *ops; unsigned long flags; - int simplex_claimed; /* Keep seperate in case we - ever need to do this locked */ + struct ata_port *simplex_claimed; /* channel owning the DMA */ struct ata_port *ports[0]; };