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? Thanks, Enric > Thanks, > Enric > > [1] https://uefi.org/pnp_id_list > > >> We internally can fix it (HID) for next generation of devices. >> >> Thanks. >> >
