From 13cc546be3060324de9d92ebde3bc9dbd950df23 Mon Sep 17 00:00:00 2001 From: Gwendal Grignou Date: Thu, 10 Jan 2008 15:47:56 +0900 Subject: [PATCH] sata_sil24: prevent hba lockup when pass-through ATA commands are used Fix commands timeout with Sil3124/3132 based HBA when pass-through ATA commands [where ATA_QCFLAG_RESULT_TF is set] are used while other commands are active on other devices connected to the same port with a Port Multiplier. Due to a hardware bug, these commands must be sent alone, like ATAPI commands. Signed-off-by: Gwendal Grignou Acked-by: Tejun Heo Signed-off-by: Jeff Garzik --- drivers/ata/sata_sil24.c | 37 ++++++++++++++++++++++++++----------- 1 file changed, 26 insertions(+), 11 deletions(-) diff --git a/drivers/ata/sata_sil24.c b/drivers/ata/sata_sil24.c index 96fd5260446..b4c674d8376 100644 --- a/drivers/ata/sata_sil24.c +++ b/drivers/ata/sata_sil24.c @@ -832,16 +832,31 @@ static int sil24_qc_defer(struct ata_queued_cmd *qc) struct ata_link *link = qc->dev->link; struct ata_port *ap = link->ap; u8 prot = qc->tf.protocol; - int is_atapi = (prot == ATA_PROT_ATAPI || - prot == ATA_PROT_ATAPI_NODATA || - prot == ATA_PROT_ATAPI_DMA); - - /* ATAPI commands completing with CHECK_SENSE cause various - * weird problems if other commands are active. PMP DMA CS - * errata doesn't cover all and HSM violation occurs even with - * only one other device active. Always run an ATAPI command - * by itself. - */ + + /* + * There is a bug in the chip: + * Port LRAM Causes the PRB/SGT Data to be Corrupted + * If the host issues a read request for LRAM and SActive registers + * while active commands are available in the port, PRB/SGT data in + * the LRAM can become corrupted. This issue applies only when + * reading from, but not writing to, the LRAM. + * + * Therefore, reading LRAM when there is no particular error [and + * other commands may be outstanding] is prohibited. + * + * To avoid this bug there are two situations where a command must run + * exclusive of any other commands on the port: + * + * - ATAPI commands which check the sense data + * - Passthrough ATA commands which always have ATA_QCFLAG_RESULT_TF + * set. + * + */ + int is_excl = (prot == ATA_PROT_ATAPI || + prot == ATA_PROT_ATAPI_NODATA || + prot == ATA_PROT_ATAPI_DMA || + (qc->flags & ATA_QCFLAG_RESULT_TF)); + if (unlikely(ap->excl_link)) { if (link == ap->excl_link) { if (ap->nr_active_links) @@ -849,7 +864,7 @@ static int sil24_qc_defer(struct ata_queued_cmd *qc) qc->flags |= ATA_QCFLAG_CLEAR_EXCL; } else return ATA_DEFER_PORT; - } else if (unlikely(is_atapi)) { + } else if (unlikely(is_excl)) { ap->excl_link = link; if (ap->nr_active_links) return ATA_DEFER_PORT; -- 2.41.1