Hi Damien,
Thanks for comments, I will submit v2.
Thanks,
~Saurav
> -----Original Message-----
> From: Damien Le Moal <dlemoal@xxxxxxxxxx>
> Sent: Friday, February 23, 2024 12:09 PM
> To: Saurav Kashyap <skashyap@xxxxxxxxxxx>; linux-ide@xxxxxxxxxxxxxxx
> Cc: soochon@xxxxxxxxxx; Manoj Phadtare <mphadtare@xxxxxxxxxxx>
> Subject: [EXT] Re: [PATCH] libata-sata: Check SDB_FIS for completion of DMA
> transfer before completing the commands.
>
> External Email
>
> ----------------------------------------------------------------------
> On 2/23/24 15:07, Saurav Kashyap wrote:
> > Sequence leading to an issue as per PCIe trace
> > - PxSact is read with slots 7 and 24 being cleared.
> > - Host starts processing these commands while data is not in system
> > memory yet.
>
> What ? If the DMA transfers are not completed yet why is the adapter clearing
> sact ? That sounds like a very nasty HW bug.
>
> > - Last pkt of 512B was sent to host.
> > - SDB.FIS is copied, telling host command slot 24 is done.
>
> And then what ? could you please descibe all of this in more detail ? What
> workloads was this ? What is the device used ? etc. This commit messsage is way
> too short to describe what seems to be a very serious bug with an adapter that
> you are not even mentioning here. Please expand this description.
>
> >
> > Cc: Soochon Radee <soochon@xxxxxxxxxx>
> > Tested-by: Manoj Phadtare <mphadtare@xxxxxxxxxxx>
> > Signed-off-by: Saurav Kashyap <skashyap@xxxxxxxxxxx>
> > ---
> > drivers/ata/libata-sata.c | 28 +++++++++++++++++++++++++++-
> > 1 file changed, 27 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/ata/libata-sata.c b/drivers/ata/libata-sata.c
> > index b6656c287175..b2310f3a2a02 100644
> > --- a/drivers/ata/libata-sata.c
> > +++ b/drivers/ata/libata-sata.c
> > @@ -14,9 +14,11 @@
> > #include <scsi/scsi_eh.h>
> > #include <linux/libata.h>
> > #include <asm/unaligned.h>
> > +#include <linux/pci.h>
> >
> > #include "libata.h"
> > #include "libata-transport.h"
> > +#include "ahci.h"
> >
> > /* debounce timing parameters in msecs { interval, duration, timeout } */
> > const unsigned int sata_deb_timing_normal[] = { 5, 100, 2000 };
> > @@ -649,6 +651,7 @@ EXPORT_SYMBOL_GPL(sata_link_hardreset);
> > int ata_qc_complete_multiple(struct ata_port *ap, u64 qc_active)
> > {
> > u64 done_mask, ap_qc_active = ap->qc_active;
> > + struct pci_dev *pdev = to_pci_dev(ap->host->dev);
> > int nr_done = 0;
> >
> > /*
> > @@ -677,7 +680,30 @@ int ata_qc_complete_multiple(struct ata_port *ap,
> u64 qc_active)
> > unsigned int tag = __ffs64(done_mask);
> >
> > qc = ata_qc_from_tag(ap, tag);
> > - if (qc) {
> > + if (pdev->vendor == PCI_VENDOR_ID_MARVELL_EXT &&
> > + (pdev->device == 0x9215 || pdev->device == 0x9235)) {
> > + struct ahci_port_priv *pp = ap->private_data;
> > + u8 *rx_fis = pp->rx_fis;
> > +
> > + if (pp->fbs_enabled)
> > + rx_fis += ap->link.pmp * AHCI_RX_FIS_SZ;
> > +
> > + if (!qc)
> > + continue;
> > +
> > + if (ata_is_ncq(qc->tf.protocol)) {
> > + u32 *fis = (u32 *)(rx_fis + RX_FIS_SDB);
> > + u32 fis_active = fis[1];
> > +
> > + if ((fis_active & (1 << tag))) {
> > + ata_qc_complete(qc);
> > + nr_done++;
> > + }
> > + } else {
> > + ata_qc_complete(qc);
> > + nr_done++;
> > + }
> > + } else if (qc) {
> > ata_qc_complete(qc);
> > nr_done++;
> > }
>
> --
> Damien Le Moal
> Western Digital Research
