[PATCH net-next] pcnet32: remove VLB support

[PATCH net-next] pcnet32: remove VLB support

[Ethan Nelson-Moore]

This allows the code managing device instances to be simplified
significantly. The VLB bus is very obsolete and last appeared on
P5 Pentium-era hardware. Support for it has been removed from
other drivers, and it is highly unlikely anyone is using it with
modern Linux kernels.

Signed-off-by: Ethan Nelson-Moore <enelsonmoore@gmail.com>
---
 drivers/net/ethernet/amd/pcnet32.c | 144 ++++-------------------------
 1 file changed, 20 insertions(+), 124 deletions(-)

diff --git a/drivers/net/ethernet/amd/pcnet32.c b/drivers/net/ethernet/amd/pcnet32.c
index 9eaefa0f5e80..7a63426af641 100644
--- a/drivers/net/ethernet/amd/pcnet32.c
+++ b/drivers/net/ethernet/amd/pcnet32.c
@@ -75,17 +75,8 @@ MODULE_DEVICE_TABLE(pci, pcnet32_pci_tbl);
 
 static int cards_found;
 
-/*
- * VLB I/O addresses
- */
-static unsigned int pcnet32_portlist[] =
-    { 0x300, 0x320, 0x340, 0x360, 0 };
-
 static int pcnet32_debug;
 static int tx_start = 1;	/* Mapping -- 0:20, 1:64, 2:128, 3:~220 (depends on chip vers) */
-static int pcnet32vlb;		/* check for VLB cards ? */
-
-static struct net_device *pcnet32_dev;
 
 static int max_interrupt_work = 2;
 static int rx_copybreak = 200;
@@ -285,13 +276,11 @@ struct pcnet32_private {
 	char			tx_full;
 	char			phycount;	/* number of phys found */
 	int			options;
-	unsigned int		shared_irq:1,	/* shared irq possible */
-				dxsuflo:1,   /* disable transmit stop on uflo */
+	unsigned int		dxsuflo:1,   /* disable transmit stop on uflo */
 				mii:1,		/* mii port available */
 				autoneg:1,	/* autoneg enabled */
 				port_tp:1,	/* port set to TP */
 				fdx:1;		/* full duplex enabled */
-	struct net_device	*next;
 	struct mii_if_info	mii_if;
 	struct timer_list	watchdog_timer;
 	u32			msg_enable;	/* debug message level */
@@ -305,7 +294,7 @@ struct pcnet32_private {
 };
 
 static int pcnet32_probe_pci(struct pci_dev *, const struct pci_device_id *);
-static int pcnet32_probe1(unsigned long, int, struct pci_dev *);
+static int pcnet32_probe1(unsigned long, struct pci_dev *);
 static int pcnet32_open(struct net_device *);
 static int pcnet32_init_ring(struct net_device *);
 static netdev_tx_t pcnet32_start_xmit(struct sk_buff *,
@@ -798,12 +787,8 @@ static void pcnet32_get_drvinfo(struct net_device *dev,
 	struct pcnet32_private *lp = netdev_priv(dev);
 
 	strscpy(info->driver, DRV_NAME, sizeof(info->driver));
-	if (lp->pci_dev)
-		strscpy(info->bus_info, pci_name(lp->pci_dev),
-			sizeof(info->bus_info));
-	else
-		snprintf(info->bus_info, sizeof(info->bus_info),
-			"VLB 0x%lx", dev->base_addr);
+	strscpy(info->bus_info, pci_name(lp->pci_dev),
+		sizeof(info->bus_info));
 }
 
 static u32 pcnet32_get_link(struct net_device *dev)
@@ -1506,28 +1491,6 @@ static const struct ethtool_ops pcnet32_ethtool_ops = {
 	.set_link_ksettings	= pcnet32_set_link_ksettings,
 };
 
-/* only probes for non-PCI devices, the rest are handled by
- * pci_register_driver via pcnet32_probe_pci */
-
-static void pcnet32_probe_vlbus(unsigned int *pcnet32_portlist)
-{
-	unsigned int *port, ioaddr;
-
-	/* search for PCnet32 VLB cards at known addresses */
-	for (port = pcnet32_portlist; (ioaddr = *port); port++) {
-		if (request_region
-		    (ioaddr, PCNET32_TOTAL_SIZE, "pcnet32_probe_vlbus")) {
-			/* check if there is really a pcnet chip on that ioaddr */
-			if ((inb(ioaddr + 14) == 0x57) &&
-			    (inb(ioaddr + 15) == 0x57)) {
-				pcnet32_probe1(ioaddr, 0, NULL);
-			} else {
-				release_region(ioaddr, PCNET32_TOTAL_SIZE);
-			}
-		}
-	}
-}
-
 static int
 pcnet32_probe_pci(struct pci_dev *pdev, const struct pci_device_id *ent)
 {
@@ -1564,7 +1527,7 @@ pcnet32_probe_pci(struct pci_dev *pdev, const struct pci_device_id *ent)
 		goto err_disable_dev;
 	}
 
-	err = pcnet32_probe1(ioaddr, 1, pdev);
+	err = pcnet32_probe1(ioaddr, pdev);
 
 err_disable_dev:
 	if (err < 0)
@@ -1588,12 +1551,9 @@ static const struct net_device_ops pcnet32_netdev_ops = {
 #endif
 };
 
-/* pcnet32_probe1
- *  Called from both pcnet32_probe_vlbus and pcnet_probe_pci.
- *  pdev will be NULL when called from pcnet32_probe_vlbus.
- */
+/* Called from pcnet_probe_pci. */
 static int
-pcnet32_probe1(unsigned long ioaddr, int shared, struct pci_dev *pdev)
+pcnet32_probe1(unsigned long ioaddr, struct pci_dev *pdev)
 {
 	struct pcnet32_private *lp;
 	int i, media;
@@ -1640,13 +1600,8 @@ pcnet32_probe1(unsigned long ioaddr, int shared, struct pci_dev *pdev)
 
 	switch (chip_version) {
 	case 0x2420:
-		chipname = "PCnet/PCI 79C970";	/* PCI */
-		break;
-	case 0x2430:
-		if (shared)
-			chipname = "PCnet/PCI 79C970";	/* 970 gives the wrong chip id back */
-		else
-			chipname = "PCnet/32 79C965";	/* 486/VL bus */
+	case 0x2430: /* Some give the wrong chip id back */
+		chipname = "PCnet/PCI 79C970";
 		break;
 	case 0x2621:
 		chipname = "PCnet/PCI II 79C970A";	/* PCI */
@@ -1752,8 +1707,7 @@ pcnet32_probe1(unsigned long ioaddr, int shared, struct pci_dev *pdev)
 		goto err_release_region;
 	}
 
-	if (pdev)
-		SET_NETDEV_DEV(dev, &pdev->dev);
+	SET_NETDEV_DEV(dev, &pdev->dev);
 
 	if (pcnet32_debug & NETIF_MSG_PROBE)
 		pr_info("%s at %#3lx,", chipname, ioaddr);
@@ -1856,7 +1810,6 @@ pcnet32_probe1(unsigned long ioaddr, int shared, struct pci_dev *pdev)
 	spin_lock_init(&lp->lock);
 
 	lp->name = chipname;
-	lp->shared_irq = shared;
 	lp->tx_ring_size = TX_RING_SIZE;	/* default tx ring size */
 	lp->rx_ring_size = RX_RING_SIZE;	/* default rx ring size */
 	lp->tx_mod_mask = lp->tx_ring_size - 1;
@@ -1920,32 +1873,10 @@ pcnet32_probe1(unsigned long ioaddr, int shared, struct pci_dev *pdev)
 	a->write_csr(ioaddr, 1, (lp->init_dma_addr & 0xffff));
 	a->write_csr(ioaddr, 2, (lp->init_dma_addr >> 16));
 
-	if (pdev) {		/* use the IRQ provided by PCI */
-		dev->irq = pdev->irq;
-		if (pcnet32_debug & NETIF_MSG_PROBE)
-			pr_cont(" assigned IRQ %d\n", dev->irq);
-	} else {
-		unsigned long irq_mask = probe_irq_on();
-
-		/*
-		 * To auto-IRQ we enable the initialization-done and DMA error
-		 * interrupts. For ISA boards we get a DMA error, but VLB and PCI
-		 * boards will work.
-		 */
-		/* Trigger an initialization just for the interrupt. */
-		a->write_csr(ioaddr, CSR0, CSR0_INTEN | CSR0_INIT);
-		mdelay(1);
-
-		dev->irq = probe_irq_off(irq_mask);
-		if (!dev->irq) {
-			if (pcnet32_debug & NETIF_MSG_PROBE)
-				pr_cont(", failed to detect IRQ line\n");
-			ret = -ENODEV;
-			goto err_free_ring;
-		}
-		if (pcnet32_debug & NETIF_MSG_PROBE)
-			pr_cont(", probed IRQ %d\n", dev->irq);
-	}
+	/* use the IRQ provided by PCI */
+	dev->irq = pdev->irq;
+	if (pcnet32_debug & NETIF_MSG_PROBE)
+		pr_cont(" assigned IRQ %d\n", dev->irq);
 
 	/* Set the mii phy_id so that we can query the link state */
 	if (lp->mii) {
@@ -1987,12 +1918,7 @@ pcnet32_probe1(unsigned long ioaddr, int shared, struct pci_dev *pdev)
 	if (register_netdev(dev))
 		goto err_free_ring;
 
-	if (pdev) {
-		pci_set_drvdata(pdev, dev);
-	} else {
-		lp->next = pcnet32_dev;
-		pcnet32_dev = dev;
-	}
+	pci_set_drvdata(pdev, dev);
 
 	if (pcnet32_debug & NETIF_MSG_PROBE)
 		pr_info("%s: registered as %s\n", dev->name, lp->name);
@@ -2100,8 +2026,7 @@ static int pcnet32_open(struct net_device *dev)
 	unsigned long flags;
 
 	if (request_irq(dev->irq, pcnet32_interrupt,
-			lp->shared_irq ? IRQF_SHARED : 0, dev->name,
-			(void *)dev)) {
+			IRQF_SHARED, dev->name, (void *)dev)) {
 		return -EAGAIN;
 	}
 
@@ -2157,7 +2082,7 @@ static int pcnet32_open(struct net_device *dev)
 	lp->a->write_csr(ioaddr, 124, val);
 
 	/* Allied Telesyn AT 2700/2701 FX are 100Mbit only and do not negotiate */
-	if (pdev && pdev->subsystem_vendor == PCI_VENDOR_ID_AT &&
+	if (pdev->subsystem_vendor == PCI_VENDOR_ID_AT &&
 	    (pdev->subsystem_device == PCI_SUBDEVICE_ID_AT_2700FX ||
 	     pdev->subsystem_device == PCI_SUBDEVICE_ID_AT_2701FX)) {
 		if (lp->options & PCNET32_PORT_ASEL) {
@@ -2970,10 +2895,9 @@ static struct pci_driver pcnet32_driver = {
 	},
 };
 
-/* An additional parameter that may be passed in... */
+/* Additional parameters that may be passed in... */
 static int debug = -1;
 static int tx_start_pt = -1;
-static int pcnet32_have_pci;
 
 module_param(debug, int, 0);
 MODULE_PARM_DESC(debug, DRV_NAME " debug level");
@@ -2985,8 +2909,6 @@ MODULE_PARM_DESC(rx_copybreak,
 		 DRV_NAME " copy breakpoint for copy-only-tiny-frames");
 module_param(tx_start_pt, int, 0);
 MODULE_PARM_DESC(tx_start_pt, DRV_NAME " transmit start point (0-3)");
-module_param(pcnet32vlb, int, 0);
-MODULE_PARM_DESC(pcnet32vlb, DRV_NAME " Vesa local bus (VLB) support (0/1)");
 module_param_array(options, int, NULL, 0);
 MODULE_PARM_DESC(options, DRV_NAME " initial option setting(s) (0-15)");
 module_param_array(full_duplex, int, NULL, 0);
@@ -3010,38 +2932,12 @@ static int __init pcnet32_init_module(void)
 	if ((tx_start_pt >= 0) && (tx_start_pt <= 3))
 		tx_start = tx_start_pt;
 
-	/* find the PCI devices */
-	if (!pci_register_driver(&pcnet32_driver))
-		pcnet32_have_pci = 1;
-
-	/* should we find any remaining VLbus devices ? */
-	if (pcnet32vlb)
-		pcnet32_probe_vlbus(pcnet32_portlist);
-
-	if (cards_found && (pcnet32_debug & NETIF_MSG_PROBE))
-		pr_info("%d cards_found\n", cards_found);
-
-	return (pcnet32_have_pci + cards_found) ? 0 : -ENODEV;
+	return pci_register_driver(&pcnet32_driver);
 }
 
 static void __exit pcnet32_cleanup_module(void)
 {
-	struct net_device *next_dev;
-
-	while (pcnet32_dev) {
-		struct pcnet32_private *lp = netdev_priv(pcnet32_dev);
-		next_dev = lp->next;
-		unregister_netdev(pcnet32_dev);
-		pcnet32_free_ring(pcnet32_dev);
-		release_region(pcnet32_dev->base_addr, PCNET32_TOTAL_SIZE);
-		dma_free_coherent(&lp->pci_dev->dev, sizeof(*lp->init_block),
-				  lp->init_block, lp->init_dma_addr);
-		free_netdev(pcnet32_dev);
-		pcnet32_dev = next_dev;
-	}
-
-	if (pcnet32_have_pci)
-		pci_unregister_driver(&pcnet32_driver);
+	pci_unregister_driver(&pcnet32_driver);
 }
 
 module_init(pcnet32_init_module);
-- 
2.43.0

Re: [PATCH net-next] pcnet32: remove VLB support

[Simon Horman]

On Tue, Jan 06, 2026 at 11:18:31PM -0800, Ethan Nelson-Moore wrote:
> This allows the code managing device instances to be simplified
> significantly. The VLB bus is very obsolete and last appeared on
> P5 Pentium-era hardware. Support for it has been removed from
> other drivers, and it is highly unlikely anyone is using it with
> modern Linux kernels.
> 
> Signed-off-by: Ethan Nelson-Moore <enelsonmoore@gmail.com>

Hi Ethan,

I don't think this driver has received much attention for some time.
So, unless you have hardware to test changes on, I would suggest
either leaving it alone or, if we suspect there are no users,
removing it.

...

Re: [PATCH net-next] pcnet32: remove VLB support

[Maciej W. Rozycki]

[+cc Thomas, linux-mips]

On Fri, 9 Jan 2026, Simon Horman wrote:

> > This allows the code managing device instances to be simplified
> > significantly. The VLB bus is very obsolete and last appeared on
> > P5 Pentium-era hardware. Support for it has been removed from
> > other drivers, and it is highly unlikely anyone is using it with
> > modern Linux kernels.
> > 
> > Signed-off-by: Ethan Nelson-Moore <enelsonmoore@gmail.com>
> 
> Hi Ethan,
> 
> I don't think this driver has received much attention for some time.
> So, unless you have hardware to test changes on, I would suggest
> either leaving it alone or, if we suspect there are no users,
> removing it.

 You mean discarding the whole of drivers/net/ethernet/amd/pcnet32.c?  If 
so, then it's a hard NAK from me.  It's the onboard/netboot interface of 
the MIPS Malta platform and it continues being used regularly, primarily 
with QEMU setups, although I have actual Malta hardware in my lab too, 
usually running 24/7.  It's one of the primary MIPS plaforms, cf. 
arch/mips/configs/malta_defconfig.

 No attention means the driver just works, why wouldn't it?  It's no 
rocket science.  FWIW I continue using several drivers that saw little to 
no change recently across various platforms.

 As to VLB support, I guess nobody cares nowadays.  I used to have such a 
system, but haven't seen one in some three decades now and never used this 
driver with one.

  Maciej

Re: [PATCH net-next] pcnet32: remove VLB support

[Thomas Bogendoerfer]

On Sun, Jan 11, 2026 at 12:40:56AM +0000, Maciej W. Rozycki wrote:
> [+cc Thomas, linux-mips]
> 
> On Fri, 9 Jan 2026, Simon Horman wrote:
> 
> > > This allows the code managing device instances to be simplified
> > > significantly. The VLB bus is very obsolete and last appeared on
> > > P5 Pentium-era hardware. Support for it has been removed from
> > > other drivers, and it is highly unlikely anyone is using it with
> > > modern Linux kernels.
> > > 
> > > Signed-off-by: Ethan Nelson-Moore <enelsonmoore@gmail.com>
> > 
> > Hi Ethan,
> > 
> > I don't think this driver has received much attention for some time.
> > So, unless you have hardware to test changes on, I would suggest
> > either leaving it alone or, if we suspect there are no users,
> > removing it.
> 
>  You mean discarding the whole of drivers/net/ethernet/amd/pcnet32.c?  If 
> so, then it's a hard NAK from me.  It's the onboard/netboot interface of 
> the MIPS Malta platform and it continues being used regularly, primarily 
> with QEMU setups, although I have actual Malta hardware in my lab too, 
> usually running 24/7.  It's one of the primary MIPS plaforms, cf. 
> arch/mips/configs/malta_defconfig.

I have a few more MIPS systems with PCnet32 chip on board. And this
driver was the first network driver for VMware. I see no reason to
remove it as it simply works.

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]

Re: [PATCH net-next] pcnet32: remove VLB support

[Simon Horman]

On Sun, Jan 11, 2026 at 12:40:56AM +0000, Maciej W. Rozycki wrote:
> [+cc Thomas, linux-mips]
> 
> On Fri, 9 Jan 2026, Simon Horman wrote:
> 
> > > This allows the code managing device instances to be simplified
> > > significantly. The VLB bus is very obsolete and last appeared on
> > > P5 Pentium-era hardware. Support for it has been removed from
> > > other drivers, and it is highly unlikely anyone is using it with
> > > modern Linux kernels.
> > > 
> > > Signed-off-by: Ethan Nelson-Moore <enelsonmoore@gmail.com>
> > 
> > Hi Ethan,
> > 
> > I don't think this driver has received much attention for some time.
> > So, unless you have hardware to test changes on, I would suggest
> > either leaving it alone or, if we suspect there are no users,
> > removing it.
> 
>  You mean discarding the whole of drivers/net/ethernet/amd/pcnet32.c?  If 
> so, then it's a hard NAK from me.  It's the onboard/netboot interface of 
> the MIPS Malta platform and it continues being used regularly, primarily 
> with QEMU setups, although I have actual Malta hardware in my lab too, 
> usually running 24/7.  It's one of the primary MIPS plaforms, cf. 
> arch/mips/configs/malta_defconfig.

Thanks, that is valuable feedback.

I'm certainly not advocating removing drivers that have an active user-base.

> 
>  No attention means the driver just works, why wouldn't it?  It's no 
> rocket science.  FWIW I continue using several drivers that saw little to 
> no change recently across various platforms.

Interesting. Subjectively, I'd say that Networking drivers it can be a sign
that the devices aren't being used in the wild. But clearly that signal was
incorrect in this case.

>  As to VLB support, I guess nobody cares nowadays.  I used to have such a 
> system, but haven't seen one in some three decades now and never used this 
> driver with one.

That is also valuable feedback, thanks.

Re: [PATCH net-next] pcnet32: remove VLB support

[Simon Horman]

On Mon, Jan 12, 2026 at 11:09:05PM +0100, Thomas Bogendoerfer wrote:
> On Sun, Jan 11, 2026 at 12:40:56AM +0000, Maciej W. Rozycki wrote:
> > [+cc Thomas, linux-mips]
> > 
> > On Fri, 9 Jan 2026, Simon Horman wrote:
> > 
> > > > This allows the code managing device instances to be simplified
> > > > significantly. The VLB bus is very obsolete and last appeared on
> > > > P5 Pentium-era hardware. Support for it has been removed from
> > > > other drivers, and it is highly unlikely anyone is using it with
> > > > modern Linux kernels.
> > > > 
> > > > Signed-off-by: Ethan Nelson-Moore <enelsonmoore@gmail.com>
> > > 
> > > Hi Ethan,
> > > 
> > > I don't think this driver has received much attention for some time.
> > > So, unless you have hardware to test changes on, I would suggest
> > > either leaving it alone or, if we suspect there are no users,
> > > removing it.
> > 
> >  You mean discarding the whole of drivers/net/ethernet/amd/pcnet32.c?  If 
> > so, then it's a hard NAK from me.  It's the onboard/netboot interface of 
> > the MIPS Malta platform and it continues being used regularly, primarily 
> > with QEMU setups, although I have actual Malta hardware in my lab too, 
> > usually running 24/7.  It's one of the primary MIPS plaforms, cf. 
> > arch/mips/configs/malta_defconfig.
> 
> I have a few more MIPS systems with PCnet32 chip on board. And this
> driver was the first network driver for VMware. I see no reason to
> remove it as it simply works.

Understood. Thanks for the valuable feedback.

Re: [PATCH net-next] pcnet32: remove VLB support

[Maciej W. Rozycki]

On Thu, 15 Jan 2026, Simon Horman wrote:

> >  No attention means the driver just works, why wouldn't it?  It's no 
> > rocket science.  FWIW I continue using several drivers that saw little to 
> > no change recently across various platforms.
> 
> Interesting. Subjectively, I'd say that Networking drivers it can be a sign
> that the devices aren't being used in the wild. But clearly that signal was
> incorrect in this case.

 A stable driver usually doesn't require attention.  A potential issue is 
using dangerous C language features or ones that have been obsoleted in a 
newer version of the standard, which cause compilation warnings or errors 
in a new version of the compiler.  But that depends on how a given driver 
was written in the first place.

  Maciej

Re: [PATCH net-next] pcnet32: remove VLB support

[David Laight]

On Tue,  6 Jan 2026 23:18:31 -0800
Ethan Nelson-Moore <enelsonmoore@gmail.com> wrote:

> This allows the code managing device instances to be simplified
> significantly. The VLB bus is very obsolete and last appeared on
> P5 Pentium-era hardware. Support for it has been removed from
> other drivers, and it is highly unlikely anyone is using it with
> modern Linux kernels.

That device bring back memories, but only the PCnet/ISA and PCnet/PCI
variants.
IIRC both are basically AMD 'lance' ethernet chips with a built-in
bus interface (the ISA one is ISA pnp).
So have a limit of 24 address bits (I don't remember using a different
ring format than any other lance variant - just for the Sun HME).
I don't remember anything about VLB - just ISA, EISA and PCI.

There are two variants of the PCnet/PCI - the '790 and '791.
Each had its own quirks, I later thought that the 791 might have
been intended to support 100M - but didn't work.

The ISA variant needed one of the ISA DMA channels put into 'cascade
mode' (the kernel didn't really want to allow that), but was about
the only ISA card capable of saturating 10M ethernet with smallish
packets (IIRC in a 33MHz 486, but not the similar 386 box).
(And 'fun' to set to fixed IO addresses on a motherboard that supported
ISA pnp for a kernel that didn't.)

One bit you might disable is the probe_vlbus() code.
You really never want that sort of probe code, it can have a disastrous
effect on other hardware at the address being probed.

I didn't 'steal' the green datasheet book :-(

	David

Re: [PATCH net-next] pcnet32: remove VLB support

[Maciej W. Rozycki]

On Thu, 15 Jan 2026, David Laight wrote:

> There are two variants of the PCnet/PCI - the '790 and '791.
> Each had its own quirks, I later thought that the 791 might have
> been intended to support 100M - but didn't work.

 FWIW the 79C973 device the Malta uses surely does support 100Mbps 
operation.

  Maciej

Re: [PATCH net-next] pcnet32: remove VLB support

[Ethan Nelson-Moore]

On Thu, Jan 15, 2026 at 2:29 PM David Laight
<david.laight.linux@gmail.com> wrote:
> One bit you might disable is the probe_vlbus() code.
> You really never want that sort of probe code, it can have a disastrous
> effect on other hardware at the address being probed.
I agree; my patch already removes that code.