Re: [PATCH v3] ata: ahci: Disallow LPM for ASUSPRO-D840SA motherboard

[Hans de Goede <hansg@kernel.org>]

Hi,

On 12-Jun-25 4:17 PM, Niklas Cassel wrote:
> A user has bisected a regression which causes graphical corruptions on his
> screen to commit 7627a0edef54 ("ata: ahci: Drop low power policy board
> type").
> 
> Simply reverting commit 7627a0edef54 ("ata: ahci: Drop low power policy
> board type") makes the graphical corruptions on his screen to go away.
> (Note: there are no visible messages in dmesg that indicates a problem
> with AHCI.)
> 
> The user also reports that the problem occurs regardless if there is an
> HDD or an SSD connected via AHCI, so the problem is not device related.
> 
> The devices also work fine on other motherboards, so it seems specific to
> the ASUSPRO-D840SA motherboard.
> 
> While enabling low power modes for AHCI is not supposed to affect
> completely unrelated hardware, like a graphics card, it does however
> allow the system to enter deeper PC-states, which could expose ACPI issues
> that were previously not visible (because the system never entered these
> lower power states before).
> 
> There are previous examples where enabling LPM exposed serious BIOS/ACPI
> bugs, see e.g. commit 240630e61870 ("ahci: Disable LPM on Lenovo 50 series
> laptops with a too old BIOS").
> 
> Since there hasn't been any BIOS update in years for the ASUSPRO-D840SA
> motherboard, disable LPM for this board, in order to avoid entering lower
> PC-states, which triggers graphical corruptions.
> 
> Cc: stable@vger.kernel.org
> Reported-by: Andy Yang <andyybtc79@gmail.com>
> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220111
> Fixes: 7627a0edef54 ("ata: ahci: Drop low power policy board type")
> Signed-off-by: Niklas Cassel <cassel@kernel.org>
> ---
> Changes since v2:
> -Rework how we handle the quirk so that we also quirk future BIOS versions
>  unless a build date is explicitly added to driver_data.
> 
>  drivers/ata/ahci.c | 19 ++++++++++++++++++-
>  1 file changed, 18 insertions(+), 1 deletion(-)

Thanks, patch looks good to me:

Reviewed-by: Hans de Goede <hansg@kernel.org>

Regards,

Hans





> diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
> index e7c8357cbc54..c8ad8ace7496 100644
> --- a/drivers/ata/ahci.c
> +++ b/drivers/ata/ahci.c
> @@ -1410,8 +1410,15 @@ static bool ahci_broken_suspend(struct pci_dev *pdev)
>  
>  static bool ahci_broken_lpm(struct pci_dev *pdev)
>  {
> +	/*
> +	 * Platforms with LPM problems.
> +	 * If driver_data is NULL, there is no existing BIOS version with
> +	 * functioning LPM.
> +	 * If driver_data is non-NULL, then driver_data contains the DMI BIOS
> +	 * build date of the first BIOS version with functioning LPM (i.e. older
> +	 * BIOS versions have broken LPM).
> +	 */
>  	static const struct dmi_system_id sysids[] = {
> -		/* Various Lenovo 50 series have LPM issues with older BIOSen */
>  		{
>  			.matches = {
>  				DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
> @@ -1440,6 +1447,13 @@ static bool ahci_broken_lpm(struct pci_dev *pdev)
>  			},
>  			.driver_data = "20180409", /* 2.35 */
>  		},
> +		{
> +			.matches = {
> +				DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
> +				DMI_MATCH(DMI_PRODUCT_VERSION, "ASUSPRO D840MB_M840SA"),
> +			},
> +			/* 320 is broken, there is no known good version yet. */
> +		},
>  		{ }	/* terminate list */
>  	};
>  	const struct dmi_system_id *dmi = dmi_first_match(sysids);
> @@ -1449,6 +1463,9 @@ static bool ahci_broken_lpm(struct pci_dev *pdev)
>  	if (!dmi)
>  		return false;
>  
> +	if (!dmi->driver_data)
> +		return true;
> +
>  	dmi_get_date(DMI_BIOS_DATE, &year, &month, &date);
>  	snprintf(buf, sizeof(buf), "%04d%02d%02d", year, month, date);
>