This is found in popular brands such as StarTech.com or Delock, and has
been a source of frustration to quite a few people, if I can trust
Amazon comments complaining about Linux support via the official
out-of-the-tree driver.

Signed-off-by: Martin Roukala (né Peres) <martin.roukala@mupuf.org>
---
I have been carrying this patch for 5+ years, without experiencing any
problem related to it... so I thought it would be a good time to start
upstreaming it and solving the lack of support for the AX99100 for more
than just me and users of my packages.
---
 drivers/tty/serial/8250/8250_pci.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
index aa1ab4da9ff1..6cfd1b2af5b7 100644
--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c
@@ -137,6 +137,8 @@ struct serial_private {
 };
 
 #define PCI_DEVICE_ID_HPE_PCI_SERIAL	0x37e
+#define PCIE_VENDOR_ID_ASIX		0x125B
+#define PCIE_DEVICE_ID_AX99100		0x9100
 
 static const struct pci_device_id pci_use_msi[] = {
 	{ PCI_DEVICE_SUB(PCI_VENDOR_ID_NETMOS, PCI_DEVICE_ID_NETMOS_9900,
@@ -149,6 +151,8 @@ static const struct pci_device_id pci_use_msi[] = {
 			 0xA000, 0x1000) },
 	{ PCI_DEVICE_SUB(PCI_VENDOR_ID_HP_3PAR, PCI_DEVICE_ID_HPE_PCI_SERIAL,
 			 PCI_ANY_ID, PCI_ANY_ID) },
+	{ PCI_DEVICE_SUB(PCIE_VENDOR_ID_ASIX, PCIE_DEVICE_ID_AX99100,
+			 0xA000, 0x1000) },
 	{ }
 };
 
@@ -920,6 +924,7 @@ static int pci_netmos_init(struct pci_dev *dev)
 	case PCI_DEVICE_ID_NETMOS_9912:
 	case PCI_DEVICE_ID_NETMOS_9922:
 	case PCI_DEVICE_ID_NETMOS_9900:
+	case PCIE_DEVICE_ID_AX99100:
 		num_serial = pci_netmos_9900_numports(dev);
 		break;
 
@@ -2544,6 +2549,14 @@ static struct pci_serial_quirk pci_serial_quirks[] = {
 		.init		= pci_netmos_init,
 		.setup		= pci_netmos_9900_setup,
 	},
+	{
+		.vendor		= PCIE_VENDOR_ID_ASIX,
+		.device		= PCI_ANY_ID,
+		.subvendor	= PCI_ANY_ID,
+		.subdevice	= PCI_ANY_ID,
+		.init		= pci_netmos_init,
+		.setup		= pci_netmos_9900_setup,
+	},
 	/*
 	 * EndRun Technologies
 	*/
@@ -6065,6 +6078,10 @@ static const struct pci_device_id serial_pci_tbl[] = {
 		0xA000, 0x3002,
 		0, 0, pbn_NETMOS9900_2s_115200 },
 
+	{	PCIE_VENDOR_ID_ASIX, PCIE_DEVICE_ID_AX99100,
+		0xA000, 0x1000,
+		0, 0, pbn_b0_1_115200 },
+
 	/*
 	 * Best Connectivity and Rosewill PCI Multi I/O cards
 	 */

---
base-commit: 1f318b96cc84d7c2ab792fcc0bfd42a7ca890681
change-id: 20260309-8250_pci_ax99100-d4ee75bbdab3

Best regards,
-- 
Martin Roukala (né Peres) <martin.roukala@mupuf.org>