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

Christian Heusel
2025-01-10T09:10:34Z

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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!

Cheers,
gromit

[0]: https://bbs.archlinux.org/viewtopic.php?id=302334

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#regzbot introduced: 7627a0edef54
#regzbot link: https://bbs.archlinux.org/viewtopic.php?id=302334
#regzbot title: ata: ahci: Blue Ray player broken since power policy change