On Thu, Jul 9, 2020 at 11:31 AM Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx> wrote: > > Hi Rafael, > > On 11/6/20 13:06, Enric Balletbo i Serra wrote: > > Hi, > > > > On 11/6/20 0:43, Dmitry Torokhov wrote: > >> On Wed, Jun 10, 2020 at 09:52:12PM +0000, Mario.Limonciello@xxxxxxxx wrote: > >>>> -----Original Message----- > >>>> From: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx> > >>>> Sent: Wednesday, June 10, 2020 4:41 PM > >>>> To: Limonciello, Mario > >>>> Cc: enric.balletbo@xxxxxxxxxxxxx; rjw@xxxxxxxxxxxxx; rafael@xxxxxxxxxx; > >>>> linux-kernel@xxxxxxxxxxxxxxx; linux-acpi@xxxxxxxxxxxxxxx; lenb@xxxxxxxxxx; > >>>> kernel@xxxxxxxxxxxxx; groeck@xxxxxxxxxxxx; bleung@xxxxxxxxxxxx; > >>>> dtor@xxxxxxxxxxxx; gwendal@xxxxxxxxxxxx; vbendeb@xxxxxxxxxxxx; > >>>> andy@xxxxxxxxxxxxx; ayman.bagabas@xxxxxxxxx; benjamin.tissoires@xxxxxxxxxx; > >>>> blaz@xxxxxxx; dvhart@xxxxxxxxxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx; > >>>> hdegoede@xxxxxxxxxx; jeremy@xxxxxxxxxxxx; 2pi@xxxxxx; > >>>> mchehab+samsung@xxxxxxxxxx; rajatja@xxxxxxxxxx; > >>>> srinivas.pandruvada@xxxxxxxxxxxxxxx; platform-driver-x86@xxxxxxxxxxxxxxx > >>>> Subject: Re: [PATCH v4] platform: x86: Add ACPI driver for ChromeOS > >>>> > >>>> > >>>> [EXTERNAL EMAIL] > >>>> > >>>> On Wed, Jun 10, 2020 at 09:28:36PM +0000, Mario.Limonciello@xxxxxxxx wrote: > >>>>>> > >>>>>> To give you some references, if I'm not wrong, this prefix is used in > >>>> all > >>>>>> or > >>>>>> almost all Intel Chromebook devices (auron, cyan, eve, fizz, hatch, > >>>>>> octopus, > >>>>>> poppy, strago ...) The ACPI source for this device can be found here > >>>> [1], > >>>>>> and, > >>>>>> if not all, almost all Intel based Chromebooks are shipped with the > >>>>>> firmware > >>>>>> that supports this. > >>>>> > >>>>> You can potentially carry a small patch in your downstream kernel for the > >>>>> legacy stuff until it reaches EOL. At least for the new stuff you could > >>>>> enact a process that properly reserves unique numbers and changes the > >>>> driver > >>>>> when the interface provided by the ACPI device has changed. > >>>> > >>>> If we use this prefix for hatch EOL is ~7 years from now. > >>>> > >>> > >>> Isn't the whole point of the ACPI registry and choosing an ID? You know internally > >>> if you need to change the interface that a new ID is needed and a new driver will > >>> be needed that comprehends that ID change. So if you can't guarantee that 0001 is > >>> the same driver interface in every firmware implementation google used then that is > >>> where this falls apart. > >>> > > > > As far as I know GGL0001 has the same driver interface in every firmware > > implementation Google used. But I'll ask to make sure. > > > >>> I know there is a long support lifecycle but you're talking about rebasing > >>> to new LTS kernels a handful of times between now and then. If the interface really > >>> is stable the patch should be small and it shouldn't be a large amount of technical > >>> debt to carry downstream until EOL. > >> > >> I think we are talking about different things actually. Let's forget > >> about Chrome OS and downstream kernels. We have devices that have > >> already been shipped and in hands of users. Some of them are old, some > >> of them are new. We can't not enforce that firmware for these devices > >> will be either released or updated. Therefore, if we want expose this > >> device in mainline kernel, we need to have it handle "GGL0001" HID in > >> addition to whatever proper HID we may select for it. > >> > > > > FWIW, after investigate a bit more, although GGL is not in the ACPI ID list it > > is in the PNP ID list [1]. So as far as I understand GGL0001 is valid ID. I know > > that PNP ID is the legacy identifier but since this was here for long time and > > will be here also for long time, I am wondering if we can take that as an > > argument to have GGL0001 as a valid device to be exposed in the kernel. > > > > So, as the GGL prefix is a valid ID in the PNP ID list, is this a valid argument > to take in consideration this patch and resolves your concern regarding the ID? Yes, it does, thanks!
