Hi,
efiboot is using ACPI UID to determine the minor number of comX.
In sys/arch/amd64/stand/efiboot/efiboot.c:
646 for (i = 0; i < sz / sizeof(EFI_HANDLE); i++) {
647 /*
648 * Identify port number of the handle. This assumes ACPI
649 * UID 0-3 map to legacy COM[1-4] and they use the legacy
650 * port address.
651 */
652 status = EFI_CALL(BS->HandleProtocol, handles[i],
&devp_guid,
653 (void **)&dp0);
654 if (EFI_ERROR(status))
655 continue;
656 uid = -1;
657 for (dp = dp0; !IsDevicePathEnd(dp);
658 dp = NextDevicePathNode(dp)) {
659 dpp = (EFI_DEV_PATH_PTR)dp;
660 if (DevicePathType(dp) == ACPI_DEVICE_PATH &&
661 DevicePathSubType(dp) == ACPI_DP)
662 if (dpp.Acpi->HID == EFI_PNP_ID(0x0501)) {
663 uid = dpp.Acpi->UID;
664 break;
665 }
666 }
667 if (uid < 0 || nitems(serios) <= uid)
668 continue;
669
670 /* Prepare SERIAL_IO_INTERFACE */
671 status = EFI_CALL(BS->HandleProtocol, handles[i],
&serio_guid,
672 (void **)&serio);
673 if (EFI_ERROR(status))
674 continue;
675 serios[uid] = serio;
676 }
677 free(handles, sz);
678
679 for (i = 0; i < nitems(serios); i++) {
680 if (serios[i] != NULL)
681 printf(" com%d", i);
682 }
I originally wrote this code, because I thought ACPI UID enumeration
is better than the order of handles by EFI.
On qemu or vmware, 2 serials mappped like the following:
EFI handle ACPI UID I/O addr efiboot kernel
0 0 0x3f8 com0 com0
1 1 0x2f8 com1 com1
EFI handle order and ACPI UID enumeration are same and they also match
I/O address assignment.
But on "HPE DL20 Gen10", 2 serials mappped like the following:
EFI handle ACPI UID I/O addr efiboot kernel
0 1 0x3f8 com1 com0
1 0 0x2f8 com0 com1
Note that EFI handle order and ACPI UID enumeration is different and
ACPI UID enumeration doesn't match the order in I/O address
assignment. In this case, since com0 or com1 are mixed up between
efiboot and kernel, if serial is usable on efiboot, it becomes not
usable on kernel.
Fortunately we can use "machine comaddr" to fix up the problem.
Also I don't know any actual case such that EFI handle order is wrong
but ACPI UID is correct. If using ACPI UID is useless, we can apply
the diff attached at last.
comment?
Index: sys/arch/amd64/stand/efiboot/efiboot.c
===================================================================
RCS file: /disk/cvs/openbsd/src/sys/arch/amd64/stand/efiboot/efiboot.c,v
retrieving revision 1.34
diff -u -p -r1.34 efiboot.c
--- sys/arch/amd64/stand/efiboot/efiboot.c 29 Nov 2019 16:16:19 -0000
1.34
+++ sys/arch/amd64/stand/efiboot/efiboot.c 22 Feb 2020 01:34:59 -0000
@@ -631,10 +631,8 @@ efi_com_probe(struct consdev *cn)
EFI_HANDLE *handles = NULL;
SERIAL_IO_INTERFACE *serio;
EFI_STATUS status;
- EFI_DEVICE_PATH *dp, *dp0;
- EFI_DEV_PATH_PTR dpp;
UINTN sz;
- int i, uid = -1;
+ int i;
cn->cn_pri = CN_LOWPRI;
cn->cn_dev = makedev(8, 0);
@@ -651,36 +649,12 @@ efi_com_probe(struct consdev *cn)
return;
}
- for (i = 0; i < sz / sizeof(EFI_HANDLE); i++) {
- /*
- * Identify port number of the handle. This assumes ACPI
- * UID 0-3 map to legacy COM[1-4] and they use the legacy
- * port address.
- */
- status = EFI_CALL(BS->HandleProtocol, handles[i], &devp_guid,
- (void **)&dp0);
- if (EFI_ERROR(status))
- continue;
- uid = -1;
- for (dp = dp0; !IsDevicePathEnd(dp);
- dp = NextDevicePathNode(dp)) {
- dpp = (EFI_DEV_PATH_PTR)dp;
- if (DevicePathType(dp) == ACPI_DEVICE_PATH &&
- DevicePathSubType(dp) == ACPI_DP)
- if (dpp.Acpi->HID == EFI_PNP_ID(0x0501)) {
- uid = dpp.Acpi->UID;
- break;
- }
- }
- if (uid < 0 || nitems(serios) <= uid)
- continue;
-
- /* Prepare SERIAL_IO_INTERFACE */
+ for (i = 0; i < sz / sizeof(EFI_HANDLE) && i < nitems(serios); i++) {
status = EFI_CALL(BS->HandleProtocol, handles[i], &serio_guid,
(void **)&serio);
if (EFI_ERROR(status))
continue;
- serios[uid] = serio;
+ serios[i] = serio;
}
free(handles, sz);
