Julian Margetson <runaway@xxxxxxxx> writes:
> On 12/19/2015 1:05 PM, Måns Rullgård wrote:
>> Andy Shevchenko <andy.shevchenko@xxxxxxxxx> writes:
>>
>>> On Sat, Dec 19, 2015 at 5:40 PM, Måns Rullgård <mans@xxxxxxxxx> wrote:
>>>
>>>> OK, I've found something. The dma setup errors are benign, caused by
>>>> the driver calling dmaengine_prep_slave_sg() even for non-dma
>>>> operations.
>>> I suppose the following is a quick fix to avoid preparing descriptor
>>> for non-DMA operations (not tested anyhow)
>>>
>>> a/drivers/ata/sata_dwc_460ex.c
>>> +++ b/drivers/ata/sata_dwc_460ex.c
>>> @@ -1041,6 +1041,9 @@ static void sata_dwc_qc_prep_by_tag(struct
>>> ata_queued_cmd *qc, u8 tag)
>>> __func__, ap->port_no, get_dma_dir_descript(qc->dma_dir),
>>> qc->n_elem);
>>>
>>> + if (!is_slave_direction(qc->dma_dir))
>>> + return;
>>> +
>>> desc = dma_dwc_xfer_setup(qc);
>>> if (!desc) {
>>> dev_err(ap->dev, "%s: dma_dwc_xfer_setup returns NULL\n",
>> I already have a better patch sitting here.
>>
>>>> The real error is the lock recursion that's reported
>>>> later. I wasn't seeing it since I was running a UP non-preempt kernel.
>>>> With lock debugging enabled, I get the same error. This patch should
>>>> fix it.
>>>> - spin_lock_irqsave(&ap->host->lock, flags);
>>>> hsdevp->cmd_issued[tag] = cmd_issued;
>>>> - spin_unlock_irqrestore(&ap->host->lock, flags);
>>>> +
>>> This will create a second empty line, though I don't care it is so minor.
>> The patch leaves one blank line before the following block comment. I
>> think it looks better that way.
>>
>
> Still can't get the patch applied .
Sorry, didn't realise it conflicted with an intervening patch I had in
my tree. Try this one.
--
Måns Rullgård
>From 97c1cdb8a6b933bad2c35b9461c2c15935f2a514 Mon Sep 17 00:00:00 2001
From: Mans Rullgard <mans@xxxxxxxxx>
Date: Sat, 19 Dec 2015 15:26:23 +0000
Subject: [PATCH] ata: sata_dwc_460ex: remove incorrect locking
This lock is already taken in ata_scsi_queuecmd() a few levels up the
call stack so attempting to take it here is an error. Moreover, it is
pointless in the first place since it only protects a single, atomic
assignment.
Signed-off-by: Mans Rullgard <mans@xxxxxxxxx>
---
drivers/ata/sata_dwc_460ex.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/drivers/ata/sata_dwc_460ex.c b/drivers/ata/sata_dwc_460ex.c
index 9985749..19d1c5e 100644
--- a/drivers/ata/sata_dwc_460ex.c
+++ b/drivers/ata/sata_dwc_460ex.c
@@ -995,15 +995,13 @@ static void sata_dwc_exec_command_by_tag(struct ata_port *ap,
struct ata_taskfile *tf,
u8 tag, u32 cmd_issued)
{
- unsigned long flags;
struct sata_dwc_device_port *hsdevp = HSDEVP_FROM_AP(ap);
dev_dbg(ap->dev, "%s cmd(0x%02x): %s tag=%d\n", __func__, tf->command,
ata_get_cmd_descript(tf->command), tag);
- spin_lock_irqsave(&ap->host->lock, flags);
hsdevp->cmd_issued[tag] = cmd_issued;
- spin_unlock_irqrestore(&ap->host->lock, flags);
+
/*
* Clear SError before executing a new command.
* sata_dwc_scr_write and read can not be used here. Clearing the PM
--
2.6.3
