From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hector Martin Subject: [PATCH] disable _BQC/_BCQ if it returns invalid values Date: Wed, 08 Jul 2009 22:16:22 +0200 Message-ID: <4A54FE96.2030407@marcansoft.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from marcansoft.com ([80.68.93.119]:49212 "EHLO smtp.marcansoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756220AbZGHUQ0 (ORCPT ); Wed, 8 Jul 2009 16:16:26 -0400 Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Zhang Rui Cc: Len Brown , linux-acpi@vger.kernel.org Validate the result of the _BQC or _BCQ method when querying the current backlight level. If the value is out of range, the support for this method is disabled. This does not break functionality as long as the hardware doesn't touch the backlight level on it own, since the driver will just use the last cached value. Acer Aspire 8930G with BIOS v1.10 (latest) has this issue. Signed-off-by: Hector Martin --- linux-2.6.30/drivers/acpi/video.c 2009-07-08 22:04:54.000000000 +0200 +++ linux-2.6.30-mod/drivers/acpi/video.c 2009-07-08 22:12:19.000000000 +0200 @@ -602,15 +605,29 @@ acpi_video_device_lcd_get_level_current( NULL, level); if (ACPI_SUCCESS(status)) { if (device->brightness->flags._BQC_use_index) { + if (*level >= (device->brightness->count - 2)) { + ACPI_WARNING((AE_INFO, + "%s is broken (returned %llu)", + buf, *level)); + device->cap._BQC = device->cap._BCQ = 0; + *level = device->brightness->curr; + return 0; + } if (device->brightness->flags._BCL_reversed) *level = device->brightness->count - 3 - (*level); *level = device->brightness->levels[*level + 2]; } - *level += bqc_offset_aml_bug_workaround; - device->brightness->curr = *level; - return 0; + if (*level > 100) { + ACPI_WARNING((AE_INFO, "%s is broken " + "(returned %llu)", buf, *level)); + device->cap._BQC = device->cap._BCQ = 0; + } else { + *level += bqc_offset_aml_bug_workaround; + device->brightness->curr = *level; + return 0; + } } else { /* Fixme: * should we return an error or ignore this failure? -- Hector Martin (hector@marcansoft.com) Public Key: http://www.marcansoft.com/marcan.asc