Re: [PATCH net] tg3: check NVRAM and control register if SRAM has the placeholder MAC address
flat view
From: Ivan Delalande <hidden>
Date: 2026-09-10 05:31:59
On Wed, Sep 09, 2026 at 07:17:51PM -0700, Jakub Kicinski wrote:
On Thu, 3 Sep 2026 16:32:55 -0700 Ivan Delalande wrote:quoted
Some of the tg3 NICs we use (BCM57762) reset the SRAM MAC address to the placeholder address on link flaps, tg3_chip_reset, etc. We've typically fixed it from userspace, but since e4c00ba7274b ("tg3: replace placeholder MAC address with device property") was merged, tg3 just fails probe as we don't have a way to get it through the generic device_get_mac_address infrastructure on our systems. Since that commit effectively made the placeholder address invalid, include this check in the earlier `addr_ok` expression, so we proceed with the NVRAM and control register fallback to find a valid MAC.If there are so many cases with known-broken MAC addresses with tg3 shouldnt we do something like:
I think we could work with this on our systems, though it would be best if the driver also checked the control register when SRAM is invalid or the default MAC. I was testing a slightly more extensive v2 based on Sashiko's comments as I agree tg3_get_device_address() is pretty awkard in its current version. But I don't have access to enough different tg3 NICs or Broadcom internal docs for a confident rewrite, so I was hoping Pavan and Michael could chime in on all of this (should we just check SRAM, NVRAM, control register, and device_get_mac_address in sequence and take the first valid non-placeholder address? should device_get_mac_address take priority over any of the other sources? should this be controlled or overridable through module parameters?). Thanks,
quoted hunk ↗ jump to hunk
--- a/drivers/net/ethernet/broadcom/tg3.c +++ b/drivers/net/ethernet/broadcom/tg3.c@@ -17914,12 +17914,13 @@ static int tg3_init_one(struct pci_dev *pdev, } err = tg3_get_device_address(tp, addr); - if (err) { - dev_err(&pdev->dev, - "Could not obtain valid ethernet address, aborting\n"); - goto err_out_apeunmap; + if (!err) { + eth_hw_addr_set(dev, addr); + } else { + dev_warn(&pdev->dev, + "Could not obtain valid ethernet address, using a random address\n"); + eth_hw_addr_random(dev); } - eth_hw_addr_set(dev, addr); intmbx = MAILBOX_INTERRUPT_0 + TG3_64BIT_REG_LOW; rcvmbx = MAILBOX_RCVRET_CON_IDX_0 + TG3_64BIT_REG_LOW;?
-- Ivan Delalande - Arista Networks