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Message-ID: <19f6cd93-9bd7-60dc-4471-18022bcf456c@molgen.mpg.de>
Date: Thu, 30 Dec 2021 12:08:05 +0100
From: Paul Menzel <pmenzel@...gen.mpg.de>
To: Damien Le Moal <damien.lemoal@...nsource.wdc.com>
Cc: linux-ide@...r.kernel.org,
Dmitry Torokhov <dmitry.torokhov@...il.com>,
Guenter Roeck <groeck@...omium.org>,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 3/3] ahci: AMD A85 FCH (Hudson D4): Skip 200 ms
debounce delay in `sata_link_resume()`
Dear Damien,
Am 30.12.21 um 03:19 schrieb Damien Le Moal:
> On 12/30/21 01:11, Paul Menzel wrote:
>> Since the first commit 1da177e4c3 (Linux-2.6.12-rc2) in the Linux git
>> repository, `sata_link_resume()` contains a 200 ms delay with the comment
>> below.
>>
>>> /*
>>> * Some PHYs react badly if SStatus is pounded
>>> * immediately after resuming. Delay 200ms before
>>> * debouncing.
>>> */
>
> This is code comment so no need to "quote" this in the commit message
> (line starting with '>'). Seeing the patch in an email client, it looks
> weird :)
Alright.
>> A lot of PHYs do not have that problem though, so delaying 200 ms increases
>> the boot time by 30 percent unnecessarily for a lot of systems, making
>> “instant booting” quite hard.
>>
>> As it’s unknown for what PHY the delay was added, create a new board
>> `board_ahci_nodbdelay` with the link flag `ATA_LFLAG_NO_DB_DELAY,`, and,
>> for now, configure the AMD A85 FCH (Hudson D4) to use it.
>>
>> On the ASUS F2A85-M PRO it reduces the Linux kernel boot time by the
>> expected 200 ms from 787 ms to 585 ms.
>>
>> Tested on ASUS F2A85-M PRO:
>>
>> Without patch, i. e., with 200 ms debounce delay:
>>
>> […]
>> [ 0.000000] DMI: ASUS F2A85-M_PRO/F2A85-M_PRO, BIOS 4.15-671-g7b043ef855 12/27/2021
>> […]
>> [ 0.404885] ahci 0000:00:11.0: version 3.0
>> [ 0.405466] ahci 0000:00:11.0: AHCI 0001.0300 32 slots 8 ports 6 Gbps 0x40 impl SATA mode
>> [ 0.405470] ahci 0000:00:11.0: flags: 64bit ncq sntf ilck led clo pio
>> [ 0.408036] scsi host0: ahci
>> [ 0.408537] scsi host1: ahci
>> [ 0.408932] scsi host2: ahci
>> [ 0.409444] scsi host3: ahci
>> [ 0.409841] scsi host4: ahci
>> [ 0.410266] scsi host5: ahci
>> [ 0.410661] scsi host6: ahci
>> [ 0.411052] scsi host7: ahci
>> [ 0.411284] ata1: DUMMY
>> [ 0.411286] ata2: DUMMY
>> [ 0.411286] ata3: DUMMY
>> [ 0.411287] ata4: DUMMY
>> [ 0.411288] ata5: DUMMY
>> [ 0.411289] ata6: DUMMY
>> [ 0.411291] ata7: SATA max UDMA/133 abar m2048@...01cc000 port 0xf01cc400 irq 19
>> [ 0.411292] ata8: DUMMY
>> […]
>> [ 0.422362] Key type encrypted registered
>> [ 0.424903] PM: Magic number: 1:28:636
>> [ 0.723979] ata7: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
>> [ 0.724268] ata7.00: ATA-9: SanDisk SDSSDP064G, 2.0.0, max UDMA/133
>> [ 0.724271] ata7.00: 125045424 sectors, multi 1: LBA48 NCQ (depth 32)
>> [ 0.725537] ata7.00: configured for UDMA/133
>> [ 0.725898] scsi 6:0:0:0: Direct-Access ATA SanDisk SDSSDP06 0 PQ: 0 ANSI: 5
>> [ 0.726428] sd 6:0:0:0: [sda] 125045424 512-byte logical blocks: (64.0 GB/59.6 GiB)
>> [ 0.726442] sd 6:0:0:0: [sda] Write Protect is off
>> [ 0.726446] sd 6:0:0:0: [sda] Mode Sense: 00 3a 00 00
>> [ 0.726464] sd 6:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
>> [ 0.727985] sda: sda1 sda2 sda3
>> [ 0.728588] sd 6:0:0:0: [sda] Attached SCSI disk
>> [ 0.738495] EXT4-fs (sda3): mounted filesystem with ordered data mode. Opts: (null). Quota mode: none.
>> […]
>> [ 0.786812] Run /sbin/init as init process
>>
>> With patch, i. e., skipping the debounce delay saves 200 ms from the boot
>> as expected.
>>
>> […]
>> [ 0.000000] DMI: ASUS F2A85-M_PRO/F2A85-M_PRO, BIOS 4.15-671-g7b043ef855 12/27/2021
>> […]
>> [ 0.407372] ahci 0000:00:11.0: version 3.0
>> [ 0.407909] ahci 0000:00:11.0: AHCI 0001.0300 32 slots 8 ports 6 Gbps 0x40 impl SATA mode
>> [ 0.407913] ahci 0000:00:11.0: flags: 64bit ncq sntf ilck led clo pio
>> [ 0.410520] scsi host0: ahci
>> [ 0.411017] scsi host1: ahci
>> [ 0.411418] scsi host2: ahci
>> [ 0.411810] scsi host3: ahci
>> [ 0.412225] scsi host4: ahci
>> [ 0.412614] scsi host5: ahci
>> [ 0.413005] scsi host6: ahci
>> [ 0.413488] scsi host7: ahci
>> [ 0.413713] ata1: DUMMY
>> [ 0.413715] ata2: DUMMY
>> [ 0.413716] ata3: DUMMY
>> [ 0.413716] ata4: DUMMY
>> [ 0.413717] ata5: DUMMY
>> [ 0.413718] ata6: DUMMY
>> [ 0.413720] ata7: SATA max UDMA/133 abar m2048@...01cc000 port 0xf01cc400 irq 19
>> [ 0.413722] ata8: DUMMY
>> […]
>> [ 0.425414] Key type encrypted registered
>> [ 0.427873] PM: Magic number: 1:234:838
>> [ 0.522131] ata7: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
>> [ 0.522415] ata7.00: ATA-9: SanDisk SDSSDP064G, 2.0.0, max UDMA/133
>> [ 0.522418] ata7.00: 125045424 sectors, multi 1: LBA48 NCQ (depth 32)
>> [ 0.523636] ata7.00: configured for UDMA/133
>> [ 0.523993] scsi 6:0:0:0: Direct-Access ATA SanDisk SDSSDP06 0 PQ: 0 ANSI: 5
>> [ 0.524497] sd 6:0:0:0: [sda] 125045424 512-byte logical blocks: (64.0 GB/59.6 GiB)
>> [ 0.524511] sd 6:0:0:0: [sda] Write Protect is off
>> [ 0.524515] sd 6:0:0:0: [sda] Mode Sense: 00 3a 00 00
>> [ 0.524534] sd 6:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
>> [ 0.525953] sda: sda1 sda2 sda3
>> [ 0.526541] sd 6:0:0:0: [sda] Attached SCSI disk
>> [ 0.536245] EXT4-fs (sda3): mounted filesystem with ordered data mode. Opts: (null). Quota mode: none.
>> […]
>> [ 0.585327] Run /sbin/init as init process
>>
>> Signed-off-by: Paul Menzel <pmenzel@...gen.mpg.de>
>> Cc: Dmitry Torokhov <dmitry.torokhov@...il.com>
>> Cc: Guenter Roeck <groeck@...omium.org>
>>
>> ---
>>
>> Add the two Chromium OS developers Dmitry and Guenter to Cc, as to my
>> knowledge Chromium/Chrome OS also tries to boot very fast, and the Chromium
>> project has some CI infrastructure.
>> ---
>> drivers/ata/ahci.c | 9 +++++++++
>> 1 file changed, 9 insertions(+)
>>
>> diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
>> index 6a2432e4adda..4f3e0603864d 100644
>> --- a/drivers/ata/ahci.c
>> +++ b/drivers/ata/ahci.c
>> @@ -51,6 +51,7 @@ enum board_ids {
>> board_ahci,
>> board_ahci_ign_iferr,
>> board_ahci_mobile,
>> + board_ahci_nodbdelay,
>
> The "nodb" naming is not super clear...
> Maybe change the name to:
>
> board_ahci_no_debounce_delay
>
> or
>
> board_ahci_no_resume_delay
>
> ?
>
> Longer, but clearer.
I agree. I followed the flag name `ATA_LFLAG_NO_DB_DELAY`.
>> board_ahci_nomsi,
>> board_ahci_noncq,
>> board_ahci_nosntf,
>> @@ -141,6 +142,13 @@ static const struct ata_port_info ahci_port_info[] = {
>> .udma_mask = ATA_UDMA6,
>> .port_ops = &ahci_ops,
>> },
>> + [board_ahci_nodbdelay] = {
>> + .flags = AHCI_FLAG_COMMON,
>> + .link_flags = ATA_LFLAG_NO_DB_DELAY,
>> + .pio_mask = ATA_PIO4,
>> + .udma_mask = ATA_UDMA6,
>> + .port_ops = &ahci_ops,
>> + },
>> [board_ahci_nomsi] = {
>> AHCI_HFLAGS (AHCI_HFLAG_NO_MSI),
>> .flags = AHCI_FLAG_COMMON,
>> @@ -437,6 +445,7 @@ static const struct pci_device_id ahci_pci_tbl[] = {
>> board_ahci_al },
>> /* AMD */
>> { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_HUDSON2_SATA_IDE), board_ahci },
>> + { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_HUDSON2_SATA_AHCI), board_ahci_nodbdelay },
>
> Patch 1 introduces this macro in pci_ids.h, but it is used only here. So
> to keep with the current style in this structure, drop the macro (so
> drop patch 1).
I wait for your answer of the second patch, and then I am going to sent v4.
>> { PCI_VDEVICE(AMD, 0x7900), board_ahci }, /* AMD CZ */
>> { PCI_VDEVICE(AMD, 0x7901), board_ahci_mobile }, /* AMD Green Sardine */
>> /* AMD is using RAID class only for ahci controllers */
Do you have a AHCI device at hand, where you could also test if
everything works fine without the delay?
Kind regards,
Paul
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