AHCI - DHRS interrupt does not stop command processing.

Not only does the DHRS interrupt not stop command processing (which means
that ahci_pm_read() needs to be single-threaded by the way, which we only do
by happenstance atm), but we were stopping and starting the port without
reloading commands in-progress.

diff --git a/sys/dev/disk/ahci/ahci.c b/sys/dev/disk/ahci/ahci.c
index 1e9a26b..6668eda 100644 (file)
--- a/sys/dev/disk/ahci/ahci.c
+++ b/sys/dev/disk/ahci/ahci.c
@@ -531,7 +531,7 @@ ahci_port_free(struct ahci_softc *sc, u_int port)
 int
 ahci_port_start(struct ahci_port *ap)
 {
-       u_int32_t       r, oldr, s, olds, is, oldis;
+       u_int32_t       r, oldr, s, olds, is, oldis, tfd, oldtfd;
 
        /*
         * FRE must be turned on before ST.  Wait for FR to go active
@@ -541,6 +541,7 @@ ahci_port_start(struct ahci_port *ap)
         */
        olds = ahci_pread(ap, AHCI_PREG_SERR);
        oldis= ahci_pread(ap, AHCI_PREG_IS);
+       oldtfd = ahci_pread(ap, AHCI_PREG_TFD);
        oldr = r = ahci_pread(ap, AHCI_PREG_CMD) & ~AHCI_PREG_CMD_ICC;
        if ((r & AHCI_PREG_CMD_FRE) == 0) {
                r |= AHCI_PREG_CMD_FRE;
@@ -557,19 +558,22 @@ ahci_port_start(struct ahci_port *ap)
        /*
         * Turn on ST, wait for CR to come up.
         */
-       s = ahci_pread(ap, AHCI_PREG_SERR);
-       is = ahci_pread(ap, AHCI_PREG_IS);
        r |= AHCI_PREG_CMD_ST;
        ahci_pwrite(ap, AHCI_PREG_CMD, r);
        if (ahci_pwait_set(ap, AHCI_PREG_CMD, AHCI_PREG_CMD_CR)) {
+               s = ahci_pread(ap, AHCI_PREG_SERR);
+               is = ahci_pread(ap, AHCI_PREG_IS);
+               tfd = ahci_pread(ap, AHCI_PREG_TFD);
                kprintf("%s: Cannot start command DMA\n"
                        "OCMD=%b OSERR=%b\n"
                        "NCMP=%b NSERR=%b\n"
-                       "OLDIS=%b\nNEWIS=%b",
+                       "OLDIS=%b\nNEWIS=%b\n"
+                       "OLDTFD=%b\nNEWTFD=%b\n",
                        PORTNAME(ap),
                        oldr, AHCI_PFMT_CMD, olds, AHCI_PFMT_SERR,
                        r, AHCI_PFMT_CMD, s, AHCI_PFMT_SERR,
-                       oldis, AHCI_PFMT_IS, is, AHCI_PFMT_IS);
+                       oldis, AHCI_PFMT_IS, is, AHCI_PFMT_IS,
+                       oldtfd, AHCI_PFMT_TFD_STS, tfd, AHCI_PFMT_TFD_STS);
                return (1);
        }
 
@@ -1996,8 +2000,13 @@ ahci_port_intr(struct ahci_port *ap, u_int32_t ci_mask)
        } else if (is & AHCI_PREG_IS_DHRS) {
                /*
                 * Command posted D2H register FIS to the rfis.  This
-                * stops command processing.  We must copy the port
-                * rfis to the ccb and restart command processing.
+                * does NOT stop command processing and it is unclear
+                * how we are supposed to deal with it other then using
+                * only a queue of 1.
+                *
+                * We must copy the port rfis to the ccb and restart
+                * command processing.  ahci_pm_read() does not function
+                * without this support.
                 */
                int     err_slot;
 
@@ -2014,8 +2023,6 @@ ahci_port_intr(struct ahci_port *ap, u_int32_t ci_mask)
                                "NCQ running\n", PORTNAME(ap));
                        err_slot = -1;
                }
-               ahci_port_stop(ap, 0);
-               ahci_port_start(ap);
        }
 
        /*