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authorPali Rohár <pali.rohar@gmail.com>2016-01-04 22:26:36 +0100
committerDarren Hart <dvhart@linux.intel.com>2016-01-19 17:35:48 -0800
commit481fe5be821c3d04f986e4061de42e1209a62374 (patch)
treebbbf6a94fdeb7f51e3182a14cb1fdbec778df62f /drivers
parent595773a493e360bdb4306a1a78669996c4842bc2 (diff)
downloadlinux-481fe5be821c3d04f986e4061de42e1209a62374.tar.bz2
dell-wmi: Process only one event on devices with interface version 0
BIOS/ACPI on devices with WMI interface version 0 does not clear buffer before filling it. So next time when BIOS/ACPI send WMI event which is smaller as previous then it contains garbage in buffer from previous event. BIOS/ACPI on devices with WMI interface version 1 clears buffer and sometimes send more events in buffer at one call. Since commit 83fc44c32ad8 ("dell-wmi: Update code for processing WMI events") dell-wmi process all events in buffer (and not just first). To prevent reading garbage from the buffer we process only the first event on devices with WMI interface version 0. Signed-off-by: Pali Rohár <pali.rohar@gmail.com> Tested-by: Gabriele Mazzotta <gabriele.mzt@gmail.com> Signed-off-by: Darren Hart <dvhart@linux.intel.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/platform/x86/dell-wmi.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/drivers/platform/x86/dell-wmi.c b/drivers/platform/x86/dell-wmi.c
index 1ad7a7b41574..5db9efbde5b9 100644
--- a/drivers/platform/x86/dell-wmi.c
+++ b/drivers/platform/x86/dell-wmi.c
@@ -237,6 +237,22 @@ static void dell_wmi_notify(u32 value, void *context)
buffer_end = buffer_entry + buffer_size;
+ /*
+ * BIOS/ACPI on devices with WMI interface version 0 does not clear
+ * buffer before filling it. So next time when BIOS/ACPI send WMI event
+ * which is smaller as previous then it contains garbage in buffer from
+ * previous event.
+ *
+ * BIOS/ACPI on devices with WMI interface version 1 clears buffer and
+ * sometimes send more events in buffer at one call.
+ *
+ * So to prevent reading garbage from buffer we will process only first
+ * one event on devices with WMI interface version 0.
+ */
+ if (dell_wmi_interface_version == 0 && buffer_entry < buffer_end)
+ if (buffer_end > buffer_entry + buffer_entry[0] + 1)
+ buffer_end = buffer_entry + buffer_entry[0] + 1;
+
while (buffer_entry < buffer_end) {
len = buffer_entry[0];