Re: [PATCH] make ata_exec_internal_sg honor DMADIR

[Vincent Pelletier <plr.vincent@gmail.com>]

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Hello,

Le lundi 20 mai 2013 20:59:29, Tejun Heo a écrit :
> Ugh... so, this is inherently racy between the probing code and admin.
> Maybe we should just implement a new libata.force param and forget
> about dynamic configuration?

Something like this ? (2/2 - untested)
Is "horkage" just another way to say "quirks" in this context ? Google 
translate doesn't help, and urbandictionary has too many entries for "hork" to 
make me confident.
Alternatively, I would add a "dflags" field to struct ata_force_param, and 
reuse ATA_DFLAG_DMADIR instead of defining a new enum item.

As this completely supersedes the atapi_dmadir module argument, is there a way 
to deprecate it (if at all a good practice) ?

> One more thing.  In the ata_exec_internal_sg(), DMADIR should be set
> iff DMA is being used, right?  So, it should also check tf->protocol.
> It prolly should test tf->protocol == ATAPI_PROT_DMA instead of cdb.

Sounds logical. I lack ATA[PI] background a lot, so I'm guessing a lot.
I updated the patch (1/2 - untested).

I should find the time to test both patches tomorrow.

Regards,
-- 
Vincent Pelletier

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From 1b491075d03ba3830296331e3c5d0e259f6803b3 Mon Sep 17 00:00:00 2001
Message-Id: <1b491075d03ba3830296331e3c5d0e259f6803b3.1369081552.git.plr.vincent@gmail.com>
In-Reply-To: <a2fe028e6736afa9d6b6612c713844c411ffca5c.1369081552.git.plr.vincent@gmail.com>
References: <a2fe028e6736afa9d6b6612c713844c411ffca5c.1369081552.git.plr.vincent@gmail.com>
From: Vincent Pelletier <plr.vincent@gmail.com>
Date: Mon, 20 May 2013 22:24:25 +0200
Subject: [2/2] [RFC] libata: Add [no]atapi_dmadir horkage

Some device require DMADIR to be enabled, but are not detected as such by
atapi_id_dmadir.
One such example is "Asus Serillel 2" SATA-host-to-PATA-device bridge: the
bridge itself requires DMADIR, even if the bridged device does not.

As atapi_dmadir module parameter can cause problems with some devices
(as per Tejun Heo's memory), enabling it globally may not be possible
depending on the hardware.

This patch adds atapi_dmadir in the form of a "force" horkage value,
allowing global, per-bus and per-device control.

Signed-off-by: Vincent Pelletier <plr.vincent@gmail.com>
---
 drivers/ata/libata-core.c |    4 +++-
 include/linux/libata.h    |    1 +
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 16c3345..e6ed443 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -2399,7 +2399,7 @@ int ata_dev_configure(struct ata_device *dev)
 			cdb_intr_string = ", CDB intr";
 		}
 
-		if (atapi_dmadir || atapi_id_dmadir(dev->id)) {
+		if (atapi_dmadir || (dev->horkage & ATA_HORKAGE_ATAPI_DMADIR) || atapi_id_dmadir(dev->id)) {
 			dev->flags |= ATA_DFLAG_DMADIR;
 			dma_dir_string = ", DMADIR";
 		}
@@ -6498,6 +6498,8 @@ static int __init ata_parse_force_one(char **cur,
 		{ "nosrst",	.lflags		= ATA_LFLAG_NO_SRST },
 		{ "norst",	.lflags		= ATA_LFLAG_NO_HRST | ATA_LFLAG_NO_SRST },
 		{ "rstonce",	.lflags		= ATA_LFLAG_RST_ONCE },
+		{ "atapi_dmadir", .horkage_on	= ATA_HORKAGE_ATAPI_DMADIR },
+		{ "noatapi_dmadir", .horkage_off = ATA_HORKAGE_ATAPI_DMADIR },
 	};
 	char *start = *cur, *p = *cur;
 	char *id, *val, *endp;
diff --git a/include/linux/libata.h b/include/linux/libata.h
index eae7a05..9a4c194 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -399,6 +399,7 @@ enum {
 	ATA_HORKAGE_BROKEN_FPDMA_AA	= (1 << 15),	/* skip AA */
 	ATA_HORKAGE_DUMP_ID	= (1 << 16),	/* dump IDENTIFY data */
 	ATA_HORKAGE_MAX_SEC_LBA48 = (1 << 17),	/* Set max sects to 65535 */
+	ATA_HORKAGE_ATAPI_DMADIR = (1 << 18),	/* device requires dmadir */
 
 	 /* DMA mask for user DMA control: User visible values; DO NOT
 	    renumber */
-- 
1.7.10.4


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From a2fe028e6736afa9d6b6612c713844c411ffca5c Mon Sep 17 00:00:00 2001
Message-Id: <a2fe028e6736afa9d6b6612c713844c411ffca5c.1369081552.git.plr.vincent@gmail.com>
From: Vincent Pelletier <plr.vincent@gmail.com>
Date: Sat, 18 May 2013 18:44:04 +0200
Subject: [1/2] libata: make ata_exec_internal_sg honor DMADIR
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

libata honors DMADIR for regular commands, but not for internal commands
used (among other) during device initialisation.

This makes SATA-host-to-PATA-device bridges based on Silicon Image SiL3611
(such as "Abit Serillel 2") end up disabled when used with an ATAPI device
after a few tries.

Log output of the bridge being hot-plugged with an ATAPI drive:

  [ 9631.212901] ata1: exception Emask 0x10 SAct 0x0 SErr 0x40c0000 action 0xe frozen
  [ 9631.212913] ata1: irq_stat 0x00000040, connection status changed
  [ 9631.212923] ata1: SError: { CommWake 10B8B DevExch }
  [ 9631.212939] ata1: hard resetting link
  [ 9632.104962] ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
  [ 9632.106393] ata1.00: ATAPI: PIONEER DVD-RW  DVR-115, 1.06, max UDMA/33
  [ 9632.106407] ata1.00: applying bridge limits
  [ 9632.108151] ata1.00: configured for UDMA/33
  [ 9637.105303] ata1.00: qc timeout (cmd 0xa0)
  [ 9637.105324] ata1.00: failed to clear UNIT ATTENTION (err_mask=0x5)
  [ 9637.105335] ata1: hard resetting link
  [ 9638.044599] ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
  [ 9638.047878] ata1.00: configured for UDMA/33
  [ 9643.044933] ata1.00: qc timeout (cmd 0xa0)
  [ 9643.044953] ata1.00: failed to clear UNIT ATTENTION (err_mask=0x5)
  [ 9643.044963] ata1: limiting SATA link speed to 1.5 Gbps
  [ 9643.044971] ata1.00: limiting speed to UDMA/33:PIO3
  [ 9643.044979] ata1: hard resetting link
  [ 9643.984225] ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 310)
  [ 9643.987471] ata1.00: configured for UDMA/33
  [ 9648.984591] ata1.00: qc timeout (cmd 0xa0)
  [ 9648.984612] ata1.00: failed to clear UNIT ATTENTION (err_mask=0x5)
  [ 9648.984619] ata1.00: disabled
  [ 9649.000593] ata1: hard resetting link
  [ 9649.939902] ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 310)
  [ 9649.955864] ata1: EH complete

With this patch, the drive enumerates correctly when libata is loaded with
atapi_dmadir=1:

  [ 9891.810863] ata1: exception Emask 0x10 SAct 0x0 SErr 0x40c0000 action 0xe frozen
  [ 9891.810874] ata1: irq_stat 0x00000040, connection status changed
  [ 9891.810884] ata1: SError: { CommWake 10B8B DevExch }
  [ 9891.810900] ata1: hard resetting link
  [ 9892.762105] ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
  [ 9892.763544] ata1.00: ATAPI: PIONEER DVD-RW  DVR-115, 1.06, max UDMA/33, DMADIR
  [ 9892.763558] ata1.00: applying bridge limits
  [ 9892.765393] ata1.00: configured for UDMA/33
  [ 9892.786063] ata1: EH complete
  [ 9892.792062] scsi 0:0:0:0: CD-ROM            PIONEER  DVD-RW  DVR-115  1.06 PQ: 0 ANSI: 5
  [ 9892.798455] sr2: scsi3-mmc drive: 12x/12x writer dvd-ram cd/rw xa/form2 cdda tray
  [ 9892.798837] sr 0:0:0:0: Attached scsi CD-ROM sr2
  [ 9892.799109] sr 0:0:0:0: Attached scsi generic sg6 type 5

Based on a patch by Csaba Halász <csaba.halasz@gmail.com> on linux-ide:
http://marc.info/?l=linux-ide&m=136121147832295&w=2

Signed-off-by: Vincent Pelletier <plr.vincent@gmail.com>
---
 drivers/ata/libata-core.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 63c743b..16c3345 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -1602,6 +1602,10 @@ unsigned ata_exec_internal_sg(struct ata_device *dev,
 	qc->tf = *tf;
 	if (cdb)
 		memcpy(qc->cdb, cdb, ATAPI_CDB_LEN);
+	if (tf->protocol == ATAPI_PROT_DMA && dev->flags & ATA_DFLAG_DMADIR &&
+	    dma_dir == DMA_FROM_DEVICE)
+		/* some SATA bridges need us to indicate data xfer direction */
+		qc->tf.feature |= ATAPI_DMADIR;
 	qc->flags |= ATA_QCFLAG_RESULT_TF;
 	qc->dma_dir = dma_dir;
 	if (dma_dir != DMA_NONE) {
-- 
1.7.10.4