Re: kern/59876 (igc0: unable to initialize)

The following reply was made to PR kern/59876; it has been noted by GNATS.

From: Shinichi Doyashiki <[email protected]>
To: [email protected]
Cc: 
Subject: Re: kern/59876 (igc0: unable to initialize)
Date: Thu, 23 Jul 2026 06:42:29 +0900

 I attempted some diagnostics, but the initialization of the igc driver fails with the error below.
 A failure in the BIOS initialization of the PCI BAR0 or similar components is a possibility,
 though I have not been able to diagnose the issue to that extent.
 
 [   1.0417554] igc0 at pci1 dev 0 function 0: Intel(R) Ethernet Controller I226-V (rev. 0x04)
 [   1.0417554] igc_set_mac_type
 [   1.0417554] igc0: PCI BAR confliction error; try PCI_ADDR_FIXUP
 [   1.0417554] igc_set_mac_type
 [   1.0417554] igc_init_mac_ops_generic
 [   1.0417554] igc_init_phy_ops_generic
 [   1.0417554] igc_init_nvm_ops_generic
 [   1.0417554] igc_init_mac_ops_generic
 [   1.0417554] igc_init_phy_ops_generic
 [   1.0417554] igc_init_nvm_ops_generic
 [   1.0417554] igc_init_mac_params_i225
 [   1.0417554] igc_init_mac_ops_generic
 [   1.0417554] igc_init_nvm_params_i225
 [   1.0417554] igc_get_flash_presence_i225
 [   1.0417554] igc_init_phy_params_i225
 [   1.0417554] igc_phy_hw_reset_generic
 [   1.0417554] igc_check_reset_block
 [   1.0417554] igc_get_phy_id
 [   1.0417554] igc_read_phy_reg_gpy
 [   1.0417554] igc_acquire_phy_base
 [   1.0417554] igc_acquire_swfw_sync_i225
 [   1.0417554] igc_get_hw_semaphore_i225
 [   1.0417554] igc_put_hw_semaphore_generic
 [   1.0417554] Driver can't access device -
 [   1.0417554] SMBI bit is set.
 [   1.0417554] PHY Initialization Error
 [   1.0417554] igc0: unable to initialize
 [   1.0417554] igc0: WARNING: power management not supported
 
 Index: if_igc.c
 ===================================================================
 RCS file: /cvsroot/src/sys/dev/pci/igc/if_igc.c,v
 retrieving revision 1.25
 diff -u -1 -0 -r1.25 if_igc.c
 --- if_igc.c	10 Jun 2026 21:02:49 -0000	1.25
 +++ if_igc.c	22 Jul 2026 21:26:09 -0000
 @@ -343,20 +343,25 @@
   *  and initializes the hardware.
   *
   *  return 0 on success, positive on failure
   *********************************************************************/
  static void
  igc_attach(device_t parent, device_t self, void *aux)
  {
  	struct pci_attach_args *pa = aux;
  	struct igc_softc *sc = device_private(self);
  	struct igc_hw *hw = &sc->hw;
 +#if 1
 +	pcireg_t rombar;
 +	pcireg_t bar0;
 +	pcireg_t bar3;
 +#endif
  
  	const struct igc_product *igcp = igc_lookup(pa);
  	KASSERT(igcp != NULL);
  
  	sc->sc_dev = self;
  	callout_init(&sc->sc_tick_ch, CALLOUT_MPSAFE);
  	callout_setfunc(&sc->sc_tick_ch, igc_tick, sc);
  	sc->sc_core_stopping = false;
  
  	sc->osdep.os_sc = sc;
 @@ -375,20 +380,45 @@
  	{
  		aprint_verbose(", 32-bit DMA");
  		sc->osdep.os_dmat = pa->pa_dmat;
  	}
  
  	pci_aprint_devinfo_fancy(pa, "Ethernet controller", igcp->igcp_name, 1);
  
  	/* Determine hardware and mac info */
  	igc_identify_hardware(sc);
  
 +#if 1
 +	/* read Expansion ROM BAR, BAR0, BAR3 */
 +	rombar = pci_conf_read(pa->pa_pc, pa->pa_tag, PCI_MAPREG_ROM);
 +	/* check ROM is disabled; then check address */
 +	if (!(rombar & PCI_MAPREG_ROM_ENABLE)) {
 +		bar0 = pci_conf_read(pa->pa_pc, pa->pa_tag, PCI_BAR0);
 +		bar3 = pci_conf_read(pa->pa_pc, pa->pa_tag, PCI_BAR3);
 +		if (PCI_MAPREG_MEM_ADDR(rombar) == PCI_MAPREG_MEM_ADDR(bar0) ||
 +		    PCI_MAPREG_MEM_ADDR(rombar) == PCI_MAPREG_MEM_ADDR(bar3)) {
 +			aprint_error_dev(sc->sc_dev, "PCI BAR confliction error; try PCI_ADDR_FIXUP\n");
 +#if 0
 +			/* trying move BAR here is no effective solution */
 +			aprint_normal_dev(sc->sc_dev, "write 0 to BAR\n");
 +			pci_conf_write(pa->pa_pc, pa->pa_tag, PCI_MAPREG_ROM, 0);
 +			rombar = pci_conf_read(pa->pa_pc, pa->pa_tag, PCI_MAPREG_ROM);
 +			aprint_normal_dev(sc->sc_dev, "read 0x%08x\n", rombar);
 +			aprint_normal_dev(sc->sc_dev, "write ~1 to BAR\n");
 +			pci_conf_write(pa->pa_pc, pa->pa_tag, PCI_MAPREG_ROM, (pcireg_t)~1);
 +			rombar = pci_conf_read(pa->pa_pc, pa->pa_tag, PCI_MAPREG_ROM);
 +			aprint_normal_dev(sc->sc_dev, "read 0x%08x\n", rombar);
 +#endif
 +		}
 +	}
 +#endif
 +
  	sc->num_tx_desc = IGC_DEFAULT_TXD;
  	sc->num_rx_desc = IGC_DEFAULT_RXD;
  
  	 /* Setup PCI resources */
  	if (igc_allocate_pci_resources(sc)) {
  		aprint_error_dev(sc->sc_dev,
  		    "unable to allocate PCI resources\n");
  		goto err;
  	}