On 10-08-19 09:40 PM, Mark Lord wrote:
Fix DSM/TRIM commands in sata_mv (v2).
These need to be issued using old-school "BM DMA",
rather than via the EDMA host queue.
Since the chips don't have proper BM DMA status,
we need to be more careful with setting the ATA_DMA_INTR bit,
since DSM/TRIM often has a long delay between "DMA complete"
and "command complete".
..
Speaking of which.. it appears that BM DMA support for sata_mv
is intentionally broken by 2.6.35 kernels, with the addition of
this code in libata-sff.c:
unsigned int ata_bmdma_qc_issue(struct ata_queued_cmd *qc)
{
struct ata_port *ap = qc->ap;
/* see ata_dma_blacklisted() */
BUG_ON((ap->flags & ATA_FLAG_PIO_POLLING) &&
qc->tf.protocol == ATAPI_PROT_DMA);
Is that BUG_ON even necessary??
It really should be looking only at tf.flags, not qp->flags there,
as it actually does redundantly further on:
WARN_ON_ONCE(qc->tf.flags & ATA_TFLAG_POLLING);
sata_mv has ATA_FLAG_PIO_POLLING set for all ports,
but doesn't set ATA_TFLAG_POLLING when doing BM DMA.
???
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