linux-kernel - Re: [PATCH] ata: ahci: Skip 200 ms debounce delay for Marvell 88SE9235

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Message-ID: <d9c4e80e-87ca-9e68-f97d-d2c709e54ff3@molgen.mpg.de>
Date:   Fri, 28 Jan 2022 10:58:45 +0100
From:   Paul Menzel <pmenzel@...gen.mpg.de>
To:     Damien Le Moal <damien.lemoal@...nsource.wdc.com>
Cc:     linux-ide@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ata: ahci: Skip 200 ms debounce delay for Marvell
 88SE9235

Dear Damien,


Thank you for the quick reply.


Am 28.01.22 um 00:40 schrieb Damien Le Moal:
> On 1/28/22 08:35, Paul Menzel wrote:
>> The 200 ms delay before debouncing the PHY in `sata_link_resume()` is
>> not needed for the Marvell 88SE9235.
>>
>>      $ lspci -nn -s 0021:0e:00.0
>>      0021:0e:00.0 SATA controller [0106]: Marvell Technology Group Ltd. 88SE9235 PCIe 2.0 x2 4-port SATA 6 Gb/s Controller [1b4b:9235] (rev 11)
>>
>> So, remove it. Tested on IBM S822LC with current Linux 5.17-rc1:
>>
>> Without this patch (with 200 ms delay):
>>
>>      [    3.358158] ata1: SATA max UDMA/133 abar m2048@...fe881000000 port 0x3fe881000100 irq 39
>>      [    3.358175] ata2: SATA max UDMA/133 abar m2048@...fe881000000 port 0x3fe881000180 irq 39
>>      [    3.358191] ata3: SATA max UDMA/133 abar m2048@...fe881000000 port 0x3fe881000200 irq 39
>>      [    3.358207] ata4: SATA max UDMA/133 abar m2048@...fe881000000 port 0x3fe881000280 irq 39
>>      […]
>>      [    3.677542] ata3: SATA link down (SStatus 0 SControl 300)
>>      [    3.677719] ata4: SATA link down (SStatus 0 SControl 300)
>>      [    3.839242] ata2: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
>>      [    3.839828] ata2.00: ATA-10: ST1000NX0313         00LY266 00LY265IBM, BE33, max UDMA/133
>>      [    3.840029] ata2.00: 1953525168 sectors, multi 0: LBA48 NCQ (depth 32), AA
>>      [    3.841796] ata2.00: configured for UDMA/133
>>      [    3.843231] ata1: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
>>      [    3.844083] ata1.00: ATA-10: ST1000NX0313         00LY266 00LY265IBM, BE33, max UDMA/133
>>      [    3.844313] ata1.00: 1953525168 sectors, multi 0: LBA48 NCQ (depth 32), AA
>>      [    3.846043] ata1.00: configured for UDMA/133
>>
>> With patch (no delay):
>>
>>      [    3.624259] ata1: SATA max UDMA/133 abar m2048@...fe881000000 port 0x3f e881000100 irq 39
>>      [    3.624436] ata2: SATA max UDMA/133 abar m2048@...fe881000000 port 0x3f e881000180 irq 39
>>      [    3.624452] ata3: SATA max UDMA/133 abar m2048@...fe881000000 port 0x3f e881000200 irq 39
>>      [    3.624468] ata4: SATA max UDMA/133 abar m2048@...fe881000000 port 0x3f e881000280 irq 39
>>      […]
>>      [    3.731966] ata3: SATA link down (SStatus 0 SControl 300)
>>      [    3.732069] ata4: SATA link down (SStatus 0 SControl 300)
>>      [    3.897448] ata1: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
>>      [    3.897678] ata2: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
>>      [    3.898140] ata1.00: ATA-10: ST1000NX0313         00LY266 00LY265IBM, BE33, max UDMA/133
>>      [    3.898175] ata2.00: ATA-10: ST1000NX0313         00LY266 00LY265IBM, BE33, max UDMA/133
>>      [    3.898287] ata1.00: 1953525168 sectors, multi 0: LBA48 NCQ (depth 32), AA
>>      [    3.898349] ata2.00: 1953525168 sectors, multi 0: LBA48 NCQ (depth 32), AA
>>      [    3.900070] ata1.00: configured for UDMA/133
>>      [    3.900166] ata2.00: configured for UDMA/133
>>
>> Signed-off-by: Paul Menzel <pmenzel@...gen.mpg.de>
>> ---
>>   drivers/ata/ahci.c | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
>> index ab5811ef5a53..edca4e8fd44e 100644
>> --- a/drivers/ata/ahci.c
>> +++ b/drivers/ata/ahci.c
>> @@ -582,6 +582,8 @@ static const struct pci_device_id ahci_pci_tbl[] = {
>>   	  .driver_data = board_ahci_yes_fbs },
>>   	{ PCI_DEVICE(PCI_VENDOR_ID_MARVELL_EXT, 0x9230),
>>   	  .driver_data = board_ahci_yes_fbs },
>> +	{ PCI_DEVICE(PCI_VENDOR_ID_MARVELL_EXT, 0x9235),
>> +	  .driver_data = board_ahci_no_debounce_delay },
>>   	{ PCI_DEVICE(PCI_VENDOR_ID_TTI, 0x0642), /* highpoint rocketraid 642L */
>>   	  .driver_data = board_ahci_yes_fbs },
>>   	{ PCI_DEVICE(PCI_VENDOR_ID_TTI, 0x0645), /* highpoint rocketraid 644L */
> 
> Looks good. But for the commit message, instead of the dmesg copy-paste,
> could you simply write the gains in terms of shortened scan time ? That
> would make it easier to understand the benefits of the patch.

I can do:

> Tested on IBM S822LC with current Linux 5.17-rc1, and the 200 ms is
> gone, and the drives are still detected.
I would still like to keep the Linux logs, as then it’s clear what I 
tested with (drives), and what ports were populated.

> Also, there is no need for the lspci output.

In my opinion, it prooves I used the correct PCI vendor and device 
codes, and also shows the revision number of the device I tested with.


Kind regards,

Paul