[RFC] patch to AHCI device detection code

[Andrey V. Elsukov]

Hi, Soren.

I'm found solution for AHCI that solve ATAPI device detection for me.
I just added waiting loop on PxTFD after reset and now my SATA DVD
detected well. Waiting time (in my case) may vary from 1ms to 900 ms.

Also AHCI spec says:

10.4.2 Port Reset
...
When PxSCTL.DET is set to 0h, upon receiving a COMINIT from
the attached device, PxTFD.STS.BSY shall be set to ’1’ by the HBA.

So we can wait until PxTFD.STS.BSY resets to zero and then
read PxSIG.

Any comments?

-- 
WBR, Andrey V. Elsukov
-------------- next part --------------
Index: src/sys/dev/ata/ata-chipset.c
===================================================================
RCS file: /ncvs/src/sys/dev/ata/ata-chipset.c,v
retrieving revision 1.219
diff -u -b -p -r1.219 ata-chipset.c
--- src/sys/dev/ata/ata-chipset.c	21 Apr 2008 10:51:38 -0000	1.219
+++ src/sys/dev/ata/ata-chipset.c	11 Jun 2008 07:17:53 -0000
@@ -1059,10 +1059,10 @@ ata_ahci_softreset(device_t dev, int por
     struct ata_pci_controller *ctlr = device_get_softc(device_get_parent(dev));
     struct ata_channel *ch = device_get_softc(dev);
     int offset = ch->unit << 7;
+    int timeout = 0;
 #ifdef AHCI_PM
     struct ata_ahci_cmd_tab *ctp =
 	(struct ata_ahci_cmd_tab *)(ch->dma.work + ATA_AHCI_CT_OFFSET);
-    int timeout = 0;
 
     /* kick controller into sane state if needed */
     ata_ahci_restart(dev);
@@ -1091,6 +1091,7 @@ ata_ahci_softreset(device_t dev, int por
 
     ata_udelay(150000);
 
+#endif
     timeout = 0;
     do {
 	    DELAY(1000);
@@ -1101,7 +1102,6 @@ ata_ahci_softreset(device_t dev, int por
     } while (ATA_INL(ctlr->r_res2, ATA_AHCI_P_TFD + offset) & ATA_S_BUSY);
     if (bootverbose)
 	device_printf(dev, "BUSY wait time=%dms\n", timeout);
-#endif
     return ATA_INL(ctlr->r_res2, ATA_AHCI_P_SIG + offset);
 }