# viaide(4): Improve VT8251 integrated SATA controller support in IDE/RAID modes.
#
# Use via_chip_map() to attach this controller in IDE and RAID modes,
# similarly to VX800, which allows drives to be identified and attached
# successfully on all four ports (two channels with master/slave ports).
#
# Use sata_setup_channel to set up its channels instead of via_setup_channel.
# This avoids writes to the 0x50 offset register, which is meaningful only
# for IDE controllers (timing control). Writing to it in the SATA controller's
# registers causes drives on the IDE controller (0x0571) not to attach at all.
# (Apply this also to the other two SATA-only controllers: VX900 and VT8261).
#
# Rename VT8237R_SATA to VT8251_SATA (0x3349 is not used for VT8237R AFAIK).
# This PCI ID is used in RAID mode on newer (CE) chipset revision and in all modes
# (IDE/RAID/AHCI) on the older one.
# Rename VT8251_SATA to VT8251_AHCI (0x6287 is used only in AHCI mode).
# Add both these IDs to the ahcisata(4) PCI quirk list.
# Add 0x5287 PCI ID used in IDE mode on newer (CE) chipset revision.
#
# For more details on these decisions, please refer to the tech-kern mailing
# list thread:
# https://mail-index.netbsd.org/tech-kern/2025/04/13/msg030365.html
#
# Should fix and close PR kern/37517.
#
# Tested on Asus A8V-VM (CD revision) and MSI MS-7318 (CE revision) motherboards.

diff --git a/sys/dev/pci/ahcisata_pci.c b/sys/dev/pci/ahcisata_pci.c
index a87086fcdd9..751df9618d8 100644
--- a/sys/dev/pci/ahcisata_pci.c
+++ b/sys/dev/pci/ahcisata_pci.c
@@ -186,10 +186,10 @@ static const struct ahci_pci_quirk ahci_pci_quirks[] = {
 	    AHCI_QUIRK_BADPMP | AHCI_QUIRK_BADNCQ },
 	{ PCI_VENDOR_ATI, PCI_PRODUCT_ATI_SB700_SATA_STORAGE,
 	    AHCI_QUIRK_BADPMP | AHCI_QUIRK_BADNCQ },
-	{ PCI_VENDOR_VIATECH, PCI_PRODUCT_VIATECH_VT8237R_SATA,
-	    AHCI_QUIRK_BADPMP },
 	{ PCI_VENDOR_VIATECH, PCI_PRODUCT_VIATECH_VT8251_SATA,
 	    AHCI_QUIRK_BADPMP },
+	{ PCI_VENDOR_VIATECH, PCI_PRODUCT_VIATECH_VT8251_AHCI,
+	    AHCI_QUIRK_BADPMP },
 	{ PCI_VENDOR_ASMEDIA, PCI_PRODUCT_ASMEDIA_ASM1061_01,
 	    AHCI_PCI_QUIRK_FORCE },
 	{ PCI_VENDOR_ASMEDIA, PCI_PRODUCT_ASMEDIA_ASM1061_02,
diff --git a/sys/dev/pci/pcidevs b/sys/dev/pci/pcidevs
index d75c1fdc04e..8a552c8d3f1 100644
--- a/sys/dev/pci/pcidevs
+++ b/sys/dev/pci/pcidevs
@@ -10127,7 +10127,7 @@ product	VIATECH VT8251		0x3287	VT8251 PCI-LPC Bridge
 product	VIATECH	VT8237A_HDA	0x3288	VT8237A/VT8251 High Definition Audio Controller
 product	VIATECH	VT8237A_ISA	0x3337	VT8237A/VT82C586A PCI-ISA Bridge
 product	VIATECH VT3314_IG	0x3344	VT3314 CN900 UniChrome Integrated Graphics
-product VIATECH VT8237R_SATA	0x3349	VT8237R Integrated SATA Controller
+product VIATECH VT8251_SATA	0x3349	VT8251 Integrated SATA Controller
 product VIATECH VT3351_HB_3351	0x3351	VT3351 Host Bridge
 product VIATECH VX800_PPB_2	0x3353	VX800/VX820 PCI-PCI Bridge
 product VIATECH P4M900_3	0x3364	CN896/P4M900 Host Bridge
@@ -10145,6 +10145,7 @@ product VIATECH VT3351_HB_4351	0x4351	VT3351 Host Bridge
 product VIATECH VX800_PMC	0x4353	VX800/VX820 Power Management Control
 product VIATECH P4M900_4	0x4364	CN896/P4M900 Host Bridge
 product VIATECH VX900_1		0x4410	VX900 Power Management Controller
+product VIATECH VT8251_SATA_2	0x5287	VT8251 Integrated SATA Controller (IDE mode)
 product VIATECH CX700M2_IDE	0x5324	CX700(M2)/VX700/VX800/VX820 IDE Controller
 product VIATECH VT8237A_SATA_2	0x5337	VT8237A Integrated SATA Controller
 product VIATECH VT3351_IOAPIC	0x5351	VT3351 I/O APIC Interrupt Controller
@@ -10153,7 +10154,7 @@ product VIATECH P4M900_IOAPIC	0x5364	CN896/P4M900 IOAPIC
 product VIATECH VT8237S_SATA	0x5372	VT8237S Integrated SATA Controller
 product VIATECH VX900_APIC	0x5410	VX900 APIC and Traffic Controller
 product VIATECH VT86C100A	0x6100	VT86C100A (Rhine-II) 10/100 Ethernet
-product VIATECH VT8251_SATA	0x6287	VT8251 Integrated SATA Controller
+product VIATECH VT8251_AHCI	0x6287	VT8251 Integrated AHCI SATA Controller
 product VIATECH VX800_SCRATCH	0x6353	VX800/VX820 Scratch Registers
 product VIATECH P4M900_6	0x6364	CN896/P4M900 Security Device
 product VIATECH VX900_SCRATCH	0x6410	VX900 Scratch Registers
diff --git a/sys/dev/pci/viaide.c b/sys/dev/pci/viaide.c
index 5631726f0fd..42b942ead1a 100644
--- a/sys/dev/pci/viaide.c
+++ b/sys/dev/pci/viaide.c
@@ -349,10 +349,24 @@ static const struct pciide_product_desc pciide_via_products[] =  {
 	  "VIA Technologies VT8237A (5337) SATA Controller",
 	  via_sata_chip_map_7,
 	},
-	{ PCI_PRODUCT_VIATECH_VT8237R_SATA,
+	/*
+	 * The 0x3349 PCI ID may be reused in all modes (IDE, RAID, AHCI).
+	 * ahcisata(4) will attach if AHCI mode is selected in the BIOS.
+	 * Newer CE revision southbridges use it only in RAID mode.
+	 */
+	{ PCI_PRODUCT_VIATECH_VT8251_SATA,
 	  0,
-	  "VIA Technologies VT8237R SATA Controller",
-	  via_sata_chip_map_7,
+	  "VIA Technologies VT8251 SATA Controller",
+	  via_chip_map,
+	},
+	/*
+	 * The 0x5287 PCI ID is used only in IDE mode for newer
+	 * VT8251 southbridge (CE) revisions.
+	 */
+	{ PCI_PRODUCT_VIATECH_VT8251_SATA_2,
+	  0,
+	  "VIA Technologies VT8251 (5287) SATA Controller",
+	  via_chip_map,
 	},
 	{ PCI_PRODUCT_VIATECH_VT8237S_SATA,
 	  0,
@@ -501,12 +515,18 @@ via_chip_map(struct pciide_softc *sc, const struct pci_attach_args *pa)
 			no_ideconf = 1;
 			/* FALLTHROUGH */
 		case PCI_PRODUCT_VIATECH_CX700_IDE:
+			sc->sc_wdcdev.sc_atac.atac_udma_cap = 6;
+			break;
+		case PCI_PRODUCT_VIATECH_VT8251_SATA:
+			/* FALLTHROUGH */
+		case PCI_PRODUCT_VIATECH_VT8251_SATA_2:
 			/* FALLTHROUGH */
 		case PCI_PRODUCT_VIATECH_VT8261_SATA:
 			/* FALLTHROUGH */
 		case PCI_PRODUCT_VIATECH_VX900_IDE:
 			/* FALLTHROUGH */
 		case PCI_PRODUCT_VIATECH_VX900_RAID:
+			sc->sc_wdcdev.sc_atac.atac_set_modes = sata_setup_channel;
 			sc->sc_wdcdev.sc_atac.atac_udma_cap = 6;
 			break;
 		default:
@@ -662,7 +682,8 @@ via_chip_map(struct pciide_softc *sc, const struct pci_attach_args *pa)
 	}
 	sc->sc_wdcdev.sc_atac.atac_pio_cap = 4;
 	sc->sc_wdcdev.sc_atac.atac_dma_cap = 2;
-	sc->sc_wdcdev.sc_atac.atac_set_modes = via_setup_channel;
+	if (sc->sc_wdcdev.sc_atac.atac_set_modes == NULL)
+		sc->sc_wdcdev.sc_atac.atac_set_modes = via_setup_channel;
 	sc->sc_wdcdev.sc_atac.atac_channels = sc->wdc_chanarray;
 	if (single_channel)
 		sc->sc_wdcdev.sc_atac.atac_nchannels = 1;