Re: Fixing sluggish performance on Thinkpad X1 Carbon 6th gen with proper BIOS settings

[Thomas Merkel]

Hello,

the sluggish high CPU utilization is basically an ACPI interrupt
storm, which has already been described in the following mailinglist
post from Martin "ACPI interrupt storm on ThinkPad T480s" [1].

I also applied the patch / workaround from Martin which solved the
issue for me. With this workaround both BIOS modes (Assist Mode:
Enable or Disabled) are working, with and without docking station.

Best regards,
Thomas

[1] https://marc.info/?l=openbsd-bugs&m=152022260714390&w=2

diff --git a/sys/dev/acpi/acpi.c b/sys/dev/acpi/acpi.c
index e4a134da02a..238bf42b08d 100644
--- a/sys/dev/acpi/acpi.c
+++ b/sys/dev/acpi/acpi.c
@@ -2209,14 +2209,24 @@ acpi_gpe(struct acpi_softc *sc, int gpe, void *arg)
        struct aml_node *node = arg;
        uint8_t mask, en;
 
-       dnprintf(10, "handling GPE %.2x\n", gpe);
-       aml_evalnode(sc, node, 0, NULL, NULL);
+       if (!sc->gpe_table[gpe].edge && gpe == 111) {
+               static unsigned short i;
+               if (i == 0) {
+                       i++;
+                       printf("acpi_gpe %d %s IGNORING\n", gpe, node->name);
+               }
+       } else {
+               printf("acpi_gpe %d %s\n", gpe, node->name);
 
-       mask = (1L << (gpe & 7));
-       if (!sc->gpe_table[gpe].edge)
-               acpi_write_pmreg(sc, ACPIREG_GPE_STS, gpe>>3, mask);
-       en = acpi_read_pmreg(sc, ACPIREG_GPE_EN,  gpe>>3);
-       acpi_write_pmreg(sc, ACPIREG_GPE_EN,  gpe>>3, en | mask);
+               dnprintf(10, "handling GPE %.2x\n", gpe);
+               aml_evalnode(sc, node, 0, NULL, NULL);
+
+               mask = (1L << (gpe & 7));
+               if (!sc->gpe_table[gpe].edge)
+                       acpi_write_pmreg(sc, ACPIREG_GPE_STS, gpe>>3, mask);
+               en = acpi_read_pmreg(sc, ACPIREG_GPE_EN,  gpe>>3);
+               acpi_write_pmreg(sc, ACPIREG_GPE_EN,  gpe>>3, en | mask);
+       }
        return (0);
 }