Commit dd65c736 authored Mar 02, 2011 by Stuart Hayes Committed by Jiri Kosina Mar 02, 2011

dcdbas: force SMI to happen when expected

The dcdbas driver can do an I/O write to cause a SMI to occur. The SMI handler
looks at certain registers and memory locations, so the SMI needs to happen
immediately. On some systems I/O writes are posted, though, causing the SMI to
happen well after the "outb" occurred, which causes random failures. Following
the "outb" with an "inb" forces the write to go through even if it is posted.

Signed-off-by: Stuart Hayes <stuart_hayes@yahoo.com>
Acked-by: Doug Warzecha <douglas_warzecha@dell.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

parent 19f52522

drivers/firmware/dcdbas.c

+3 −1

Original line number	Original line	Diff line number	Diff line
	@@ -268,8 +268,10 @@ int dcdbas_smi_request(struct smi_cmd *smi_cmd)
	}		}

	/* generate SMI */		/* generate SMI */
			/* inb to force posted write through and make SMI happen now */
	asm volatile (		asm volatile (
	"outb %b0,%w1"		"outb %b0,%w1\n"
			"inb %w1"
	: /* no output args */		: /* no output args */
	: "a" (smi_cmd->command_code),		: "a" (smi_cmd->command_code),
	"d" (smi_cmd->command_address),		"d" (smi_cmd->command_address),