Re: [patch 05/25] ata: add the SW NCQ support to sata_nv for MCP51/MCP55/MCP61

[Zoltan Boszormenyi <zboszor@dunaweb.hu>]

Jeff Garzik írta:
> Zoltan Boszormenyi wrote:
>> Hi,
>>
>> Jeff Garzik írta:
>>> akpm@linux-foundation.org wrote:
>>>> From: Kuan Luo <kluo@nvidia.com>
>>>>
>>>> Add the Software NCQ support to sata_nv.c for MCP51/MCP55/MCP61 SATA
>>>> controller.  NCQ function is disable by default, you can enable it 
>>>> with
>>>> 'swncq=1'.  NCQ will be turned off if the drive is Maxtor on MCP51 
>>>> or MCP55
>>>> rev 0xa2 platform.
>>>>
>>>> [akpm@linux-foundation.org: build fix]
>>>> Signed-off-by: Kuan Luo <kluo@nvidia.com>
>>>> Signed-off-by: Peer Chen <pchen@nvidia.com>
>>>> Cc: Zoltan Boszormenyi <zboszor@dunaweb.hu>
>>>> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
>>>> ---
>>>>
>>>>  drivers/ata/sata_nv.c |  860 +++++++++++++++++++++++++++++++++++++++-
>>>>  1 files changed, 851 insertions(+), 9 deletions(-)
>>>
>>> I finally gave this a thorough review.
>>>
>>> Overall, good work.  The state transitions all seem solid.  I made 
>>> several minor changes and cleanups, and checked it into the 
>>> 'nv-swncq' branch of 
>>> git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev.git
>>>
>>> Two hurdles before I'm ready to push upstream:
>>>
>>> * someone please verify my minor changes did not break anything; I 
>>> don't have real hardware
>>
>> After reading the diff between the original and your cleaned up version
>> it seems both the change from 4 individual flags to a single integer 
>> and the
>> nv_swncq_bmdma_stop() -> __ata_bmdma_stop() transition are obviously 
>> correct.
>> I attached a small cleanup patch which may make one check a bit more 
>> readable.
>>
>> However, can you explain this chunk below? Why isn't it needed?
>>
>> @@ -615,7 +622,6 @@ static const struct ata_port_info nv_por
>>        {
>>                .sht            = &nv_swncq_sht,
>>                .flags          = ATA_FLAG_SATA | ATA_FLAG_NO_LEGACY,
>> -               .link_flags     = ATA_LFLAG_HRST_TO_RESUME,
>>                .pio_mask       = NV_PIO_MASK,
>>                .mwdma_mask     = NV_MWDMA_MASK,
>>                .udma_mask      = NV_UDMA_MASK,
>
> that's a bug.  fixed.
>
> I also applied your cleanup.

Thanks, but you took the wrong cleanup patch.
My original, i.e. this chunk below is wrong.

@@ -2291,8 
<http://git.kernel.org/?p=linux/kernel/git/jgarzik/libata-dev.git;a=blob;f=drivers/ata/sata_nv.c;h=540f218e10e56c8a85a937bc920a5d96434bcc8f;hb=41f0f8af3edfccd58b5c9d714928d773a072b693#l2291> 
+2283,7 
<http://git.kernel.org/?p=linux/kernel/git/jgarzik/libata-dev.git;a=blob;f=drivers/ata/sata_nv.c;h=ffd00f5c533d7b58dde67cfef7d2191ca15ea140;hb=5a5a9e1890b8260686218a68862d880daee1a817#l2283> 
@@ static void nv_swncq_host_interrupt(struct ata_port *ap, u16 fis)
                 */
                pp->dhfis_bits |= (0x1 << pp->last_issue_tag);
                pp->ncq_flags |= ncq_saw_d2h;
-               if ((pp->ncq_flags & ncq_saw_sdb) ||
-                   (pp->ncq_flags & ncq_saw_backout)) {
+               if (pp->ncq_flags & (ncq_saw_sdb || ncq_saw_backout)) {
                        ata_ehi_push_desc(ehi, "illegal fis transaction");
                        ehi->err_mask |= AC_ERR_HSM;
                        ehi->action |= ATA_EH_HARDRESET;

It should be a binary OR between the flags. This caused immediate
NCQ errors upon boot and lead to disabling NCQ.
My second patch has it corrected.

Best regards,
Zoltán Böszörményi