The ATA_CMD_READ_LOG_DMA_EXT can cause controller/device to become unresponsive until the next power cycle. This seems to particularly affect IDE to SATA adapters, possibly in combination with certain SATA SSDs, though there might be more/different cases. Comment 5 of https://bugzilla.kernel.org/show_bug.cgi?id=195895 is an example. Having an option to disable its use allows booting systems affected, which besides being a useful workaround is also a necessary step to allow gathering more debug info on these systems. Existing workarounds like forcing PIO mode do not work (in addition to the performance issues) because READ_LOG_DMA is issued even if PIO mode is forced. Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@xxxxxx> --- Documentation/admin-guide/kernel-parameters.txt | 2 ++ drivers/ata/libata-core.c | 2 ++ 2 files changed, 4 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index bdb22006f713..191502e8fa74 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2551,6 +2551,8 @@ * [no]ncqtrim: Turn off queued DSM TRIM. + * [no]dmalog: Turn off use of ATA_CMD_READ_LOG_DMA_EXT (0x47) command + * nohrst, nosrst, norst: suppress hard, soft and both resets. diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c index 61c762961ca8..7fb865333a38 100644 --- a/drivers/ata/libata-core.c +++ b/drivers/ata/libata-core.c @@ -6104,6 +6104,8 @@ static int __init ata_parse_force_one(char **cur, { "ncq", .horkage_off = ATA_HORKAGE_NONCQ }, { "noncqtrim", .horkage_on = ATA_HORKAGE_NO_NCQ_TRIM }, { "ncqtrim", .horkage_off = ATA_HORKAGE_NO_NCQ_TRIM }, + { "nodmalog", .horkage_on = ATA_HORKAGE_NO_DMA_LOG }, + { "dmalog", .horkage_off = ATA_HORKAGE_NO_DMA_LOG }, { "dump_id", .horkage_on = ATA_HORKAGE_DUMP_ID }, { "pio0", .xfer_mask = 1 << (ATA_SHIFT_PIO + 0) }, { "pio1", .xfer_mask = 1 << (ATA_SHIFT_PIO + 1) }, -- 2.32.0
