On Thu, Feb 13, 2014 at 11:08 AM, Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> wrote: > On Thu, Feb 13, 2014 at 05:10:25PM +0800, Aaron Lu wrote: >> On 02/12/2014 06:31 PM, Chris Wilson wrote: >> > On Wed, Feb 12, 2014 at 11:05:40AM +0800, Aaron Lu wrote: >> >> The ACPI table on ASUS UX302LA has more than 8 output devices under the >> >> graphics controller device node. The problem is, the real active output >> >> device, the LCD panel, is listed the last. The result is, the LCD's >> >> device id doesn't get recorded in the active device list CADL array and >> >> when the _DCS control method for the LCD device is executed, it returns >> >> 0x1d, meaning it is not active. This affects the hotkey delivery ASL >> >> code that will not deliver a notification if the output device is not >> >> active on backlight hotkey press. >> >> >> >> I don't see a clean way to solve this problem since the operation region >> >> spec doesn't allow more than 8 output devices so we have no way of >> >> storing all these output devices. The fact that output devices that have >> >> _BCM control method usually means they have a higher possibility of being >> >> used than those who don't made me choose a simple way to work around >> >> the buggy firmware by replacing the last entry in CADL array with the one >> >> that has _BCM control method. There is no specific reason why the last >> >> entry is picked instead of others. >> > >> > Another possibility is that the connector list is in rough priority >> > order so might be useful for sorting the CADL array. >> > >> > Since the CADL should only be a list of currently active devices, we >> > could just bite the bullet and repopulate it correctly after every >> > setcrtc. >> >> Thanks for the suggestion. As a first step, does the following un-tested >> patch look OK? > > Yes. Maybe worth putting together the similar routines for blind > setting the didl and the cadl, or at least for computing the value from > the connector. For instance, the didl logic disagrees with the value of > index - is that relevant? I have a suspicion that the CADL entry should > match the DIDL entry for the connector, but that is not actually > mentioned in the opregion spec afaict. I think a problem is that often we have more than one output for a given type. So we need to somehow match them up to make sure we put the right ones intot didl/cadl lists. The issue here is that our connectors don't match up perfectly with the acpi output entries (since we have separate dp/hdmi outputs). But I think it would be worthwhile trying to match them up and store a link from struct intel_connector to the right acpi node acpi node. Then we could generate the didl/cadl lists by walking all connectors (only looking at the enabled ones for cadl) and evaluating the _ADR node of the linked apci node. As long as we ensure that we don't have duplicated entries we should be fine. This is a bit more work though ... And I have no idea really how firmware uses these lists (besides for backlight purposes apparently). -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
