Re: [REGRESSION][BISECTED] BU40N Blu-Ray drive broken since 7627a0edef54

[Niklas Cassel]

On Fri, Jan 10, 2025 at 10:04:46AM +0100, Christian Heusel wrote:
> Hello everyone,
> 
> we have recently received a report by a user in the Arch Linux Forums
> user that their Blue Ray player, a HL-DT-ST BD-RE BU40N stopped working
> somewhere since kernel version v6.8.0. We have then bisected the issue
> together with them within the mainline kernel sources to the following
> commit that changes the default power policy:
> 
>     7627a0edef54 ("ata: ahci: Drop low power policy board type")
> 
> The user reports that adding "ahci.mobile_lpm_policy=1" as a kernel
> parameter fixes the issue for them.
> 
> Additionally fellow forum user @loqs came up with a quirk patch, that
> sadly was reported to not work:
> 
> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
> index c085dd8..ef01ccd 100644
> --- a/drivers/ata/libata-core.c
> +++ b/drivers/ata/libata-core.c
> @@ -4118,6 +4118,9 @@ static const struct ata_dev_quirks_entry __ata_dev_quirks[] = {
>  	{ "SAMSUNG MZ7TD256HAFV-000L9", NULL,       ATA_QUIRK_NOLPM },
>  	{ "SAMSUNG MZ7TE512HMHP-000L1", "EXT06L0Q", ATA_QUIRK_NOLPM },
>  
> +	/* Hitachi-LG Data Storage models with LPM issues */
> +	{ "HL-DT-ST BD-RE BU40N", NULL, ATA_QUIRK_NOLPM },
> +
>  	/* devices that don't properly handle queued TRIM commands */
>  	{ "Micron_M500IT_*",		"MU01",	ATA_QUIRK_NO_NCQ_TRIM |
>  						ATA_QUIRK_ZERO_AFTER_TRIM },
> 
> So if anyone has feedback on why the patch does not work or any
> alternative ideas for a solution that would be highly appreciated!

It would be nice if you could share a dmesg.

If you have applied the quirk properly, I would expect to see something
similar to:

[    2.989363] ata2.00: Model 'QEMU DVD-ROM', rev '2.5+', applying quirks: nolpm


Kind regards,
Niklas