On Thu, Jun 01, 2017 at 01:28:31PM +0000, Narendra.K@xxxxxxxx wrote: > > -----Original Message----- > > From: Jean Delvare [mailto:jdelvare@xxxxxxx] > > Sent: Thursday, June 1, 2017 6:08 PM > > To: x86@xxxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx > > Cc: K, Narendra <Narendra_K@xxxxxxxx>; Hargrave, Jordan > > <Jordan_Hargrave@xxxxxxxx>; Iyer, Shyam <Shyam_Iyer@xxxxxxxx>; Bjorn > > Helgaas <bhelgaas@xxxxxxxxxx> > > Subject: dmi type 0xB1 record - unknown flag > > > > Hi all, > > > > Hi Jean, > > > I see the following message in my kernel log: > > > > dmi type 0xB1 record - unknown flag > > > > This is on a Dell Optiplex 9020 workstation. I see the message comes > > from: > > > > static void __init read_dmi_type_b1(const struct dmi_header *dm, > > void *private_data) { > > (...) > > switch (((*(u32 *)d) >> 9) & 0x03) { > > case 0x00: > > printk(KERN_INFO "dmi type 0xB1 record - unknown flag\n"); > > break; > > > > What is the value of this message? Is there anything which needs > > to be done to properly support such systems? > > This function was added to avoid adding systems to the > 'pciprobe_dmi_table' and set breadth first sorting in a generic way. > > This flag is a hint to indicate the sort method to be used. The > value 0x01 indicates that PCI breadth first sort be used. ' > find_sort_method' function checks if smbios_type_b1_flag is set to 1 > and if yes, calls 'set_bf_sort '. This function sets ' pci_bf_sort' > to 'pci_dmi_bf'. > > The value 0x00 is not a valid value. When the flag is 0x00, the sort > method will be the default that is decided by the kernel. > > There is no additional handling required for such a system. That was added by 6e8af08dfa40 ("PCI: enable pci=bfsort by default on future Dell systems"). The fact that BIOS supplied a B1 record with an unknown value (0) looks like a Dell BIOS defect, which is ironic, considering that Dell added this thing in the first place. I think we should remove the message, since it is alarming to users and they can't do anything about it anyway. Bjorn
