On Thu, May 14, 2009 at 09:22:24AM +0800, yakui_zhao wrote: > On Thu, 2009-05-14 at 02:57 +0800, Jesse Barnes wrote: > > In the i915 driver we want to know if the lid is open or closed and > > when its status changes, since we want to use the closed state to > > indicate that the LFP is unavailable (disconnected in KMS terms) and > > open to indicate that it's usable. > > > > To that end, this patch adds some code to the ACPI button driver to > > send us lid notifications as they occur and provide us with current lid > > status when called. > > > > It's a bit ugly, and I don't handle the inter-module dependencies very > > well at this point, but you should get the idea. > The tight module dependency. If the ACPI button is compiled as module > and i915 is compiled as built-in kernel, we will fail in kernel > compilation. Yes, it needs a Kconfig fixup. > > There's also a policy question here. On some machines, a lid close > > will cause the ACPI firmware to program the GPU, disabling the pipe > > associated with the panel. Should we detect this and turn it back on > > at open time? That could be dangerous if userspace has received the > > LVDS hotplug event and changed the config out from under us... > > > > Comments? > It seems that the LID status is used to determine whether the LVDS is > connected. > It is not reliable. On some boxes the initial LID status is incorrect. > Maybe the LID status is open. But the ACPI returns that the LID is > close. In such case the LVDS is not initialized and user can't get the > output. Really? I haven't seen any cases of this. They'll fail in all sorts of fun ways with modern userland. -- Matthew Garrett | mjg59@xxxxxxxxxxxxx -- 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
