Re: [PATCH 1/2] ata: ahci: Refactor ahci_broken_lpm()

[Niklas Cassel <cassel@kernel.org>]

Hello Hans,

On Mon, Jun 09, 2025 at 04:49:17PM +0200, Hans de Goede wrote:
> On 9-Jun-25 3:45 PM, Niklas Cassel wrote:
> > Currently, the match table in ahci_broken_lpm() contains DMI BIOS dates
> > of BIOSes that are known to be working.
> > 
> > Having a list of known to be working versions is usually the wrong way to
> > do things (as this list could theoretically be infinite).
> > 
> > Refactor this match table to contain DMI BIOS dates of BIOSes that are
> > known to not be working, such that this list can be extended with BIOS
> > versions (for other boards) that are known to not be working, where there
> > is no good BIOS version (because all released versions are broken).
> > 
> > Signed-off-by: Niklas Cassel <cassel@kernel.org>
> > ---
> >  drivers/ata/ahci.c | 34 ++++++++++++++++++++++++----------
> >  1 file changed, 24 insertions(+), 10 deletions(-)
> > 
> > diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
> > index 163ac909bd06..a6ce172fa928 100644
> > --- a/drivers/ata/ahci.c
> > +++ b/drivers/ata/ahci.c
> > @@ -1411,27 +1411,39 @@ static bool ahci_broken_suspend(struct pci_dev *pdev)
> >  static bool ahci_broken_lpm(struct pci_dev *pdev)
> >  {
> >  	static const struct dmi_system_id sysids[] = {
> > -		/* Various Lenovo 50 series have LPM issues with older BIOSen */
> > +		/* Table contains DMI BIOS dates of BIOSes with broken LPM. */
> >  		{
> >  			.matches = {
> >  				DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
> >  				DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X250"),
> >  			},
> > -			.driver_data = "20180406", /* 1.31 */
> > +			/*
> > +			 * 1.31, released 20180406, has working LPM, mark any
> > +			 * DMI BIOS date before that as broken.
> > +			 */
> 
> Note the DMI_BIOS_DATE field is the data the BIOS was build, I would avoid
> the word "released" here since release-notes doucments often contain different
> dates then the actual build date (e.g. see below).

Hm... the command to get this date is:
$ dmidecode -s bios-release-date

So in one way, I think this is the correct term.

But indeed, the "release date" in the release notes is usually different
from the "dmidecode -s bios-release-date" date, so perhaps just to avoid
confusion, using "build date" rather than "released"/"release date" is a
good idea.


> 
> > +			.driver_data = "20180405",
> >  		},
> >  		{
> >  			.matches = {
> >  				DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
> >  				DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad L450"),
> >  			},
> > -			.driver_data = "20180420", /* 1.28 */
> > +			/*
> > +			 * 1.28, released 20180420, has working LPM, mark any
> > +			 * DMI BIOS date before that as broken.
> > +			 */
> > +			.driver_data = "20180419",
> >  		},
> >  		{
> >  			.matches = {
> >  				DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
> >  				DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T450s"),
> >  			},
> > -			.driver_data = "20180315", /* 1.33 */
> > +			/*
> > +			 * 1.33, released 20180315, has working LPM, mark any
> > +			 * DMI BIOS date before that as broken.
> > +			 */
> > +			.driver_data = "20180314",
> >  		},
> >  		{
> >  			.matches = {
> > @@ -1439,12 +1451,14 @@ static bool ahci_broken_lpm(struct pci_dev *pdev)
> >  				DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad W541"),
> >  			},
> >  			/*
> > -			 * Note date based on release notes, 2.35 has been
> > -			 * reported to be good, but I've been unable to get
> > -			 * a hold of the reporter to get the DMI BIOS date.
> > -			 * TODO: fix this.
> > +			 * Note: according to release notes, version 2.35 has
> > +			 * working LPM, but we do not have the DMI BIOS date for
> > +			 * this version, so the date, 20180310, is based on the
> > +			 * release notes. Mark any DMI BIOS date before that as
> > +			 * broken.
> > +			 * TODO: find with date with DMI BIOS date.
> >  			 */
> > -			.driver_data = "20180310", /* 2.35 */
> > +			.driver_data = "20180309",
> 
> This reminds me that I did eventually got the actual BIOS date from
> the reporter. After some digging I managed to find the email.
> 
> The first known working BIOS has a BIOS date of 04/09/2018 so that
> would become "20180409" before your patch / "20180408" after your patch.
> 
> I guess you may want to add a prep patch before the rest of this
> series before this patch to make things a bit cleaner.

Thank you!

I will send a V2 with the proper date as a patch 1/3.


Kind regards,
Niklas