kernel: ahci: Document workaround

Documents a workaround for a possible hw/emulation quirk

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/sys/dev/ic/ahci.c b/sys/dev/ic/ahci.c
index 43b4d1d..14dbf74 100644
--- a/sys/dev/ic/ahci.c
+++ b/sys/dev/ic/ahci.c
@@ -444,6 +444,12 @@ ahci_reset_port(struct hba_port *port)
 {
     uint32_t sctl, ssts;
 
+    /*
+     * Some odd behaviour may occur if a COMRESET is sent
+     * to the port while it is in an idle state...
+     * A workaround to this is to bring the port up
+     * then immediately transmit the COMRESET to the device.
+     */
     ahci_start_port(port);
     sctl = mmio_read32(&port->sctl);