From: Matthew Dillon <dillon@apollo.backplane.com>
Date: Mon, 11 Jun 2018 20:21:53 +0000 (-0700)
Subject: kernel - Improve ACPI compatibility with older BIOSes
X-Git-Tag: v5.5.0~505
X-Git-Url: https://gitweb.dragonflybsd.org/dragonfly.git/commitdiff_plain/dd62cb1009be64311a6460315301e1a6f3a88e04

kernel - Improve ACPI compatibility with older BIOSes

* ACPI alignment field in ACPI resources can sometimes be 0, leading
  to passing 0 for 'align' to acpi_res_set_iorange() which panics the
  box with a division-by-zero fault.

* Relax handling of this argument by setting it to 1 if it is found
  to be 0.

* Fixes DFly panics with certain older BIOSes.

Reported-by: myu
---

diff --git a/sys/dev/acpica/acpi_resource.c b/sys/dev/acpica/acpi_resource.c
index e689932448..6730524f7c 100644
--- a/sys/dev/acpica/acpi_resource.c
+++ b/sys/dev/acpica/acpi_resource.c
@@ -527,6 +527,8 @@ acpi_res_set_iorange(device_t dev, void *context, uint64_t low,
 
     if (cp == NULL)
 	return;
+    if (align == 0)	/* broken acpi resources might pass align == 0 */
+	align = 1;
 
     base = roundup(low, align);
     if (base + length - 1 <= high) {