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From: Daniel Dadap <ddadap@nvidia.com>
To: "Barnabás Pőcze" <pobrn@protonmail.com>
Cc: <platform-driver-x86@vger.kernel.org>, <hdegoede@redhat.com>,
	<mario.limonciello@outlook.com>, <andy@infradead.org>,
	<dvhart@infradead.org>, Aaron Plattner <aplattner@nvidia.com>
Subject: Re: [PATCH v3] platform/x86: Add driver for ACPI WMAA EC-based backlight control
Date: Fri, 27 Aug 2021 11:47:12 -0500	[thread overview]
Message-ID: <673a1641-cfdf-1857-21ea-a12867749912@nvidia.com> (raw)
In-Reply-To: <9f9ca8a0-491d-7493-5459-8f81687f2d47@nvidia.com>

On 8/25/21 5:26 PM, Daniel Dadap wrote:
> On 8/24/21 5:47 PM, Barnabás Pőcze wrote:
>> Have you looked at `devm_backlight_device_register()`?
>
>
> So regarding this suggestion, I have switched to 
> devm_backlight_device_register(), but now I can't unload the module; 
> it fails with EBUSY. I tried unbinding the device (via 
> /sys/class/backlight/wmaa_backlight/device/driver/unbind), but that 
> fails with ENODEV, maybe due to missing plumbing in wmi?
>
> I'm not sure if it's expected for users to be able to unload their 
> backlight drivers; on the random selection of notebooks that I have 
> immediately available to me at the moment, the backlight driver is 
> registered by the GPU driver, and that tends to be not unloadable 
> because e.g. it's driving the console.
>
> It's probably best to use devm_backlight_device_register() anyway 
> since it seems the ordinary backlight_device_register() is deprecated, 
> but I wanted to see if there were any strong opinions about whether it 
> would be a problem that the driver can't be unloaded.
>

Okay, actually, I *can* unbind the device; I was apparently pasting a 
truncated GUID into the shell so it wasn't finding it. However, even 
after successfully unbinding, I still can't unload the module; it still 
fails with EBUSY, even if I explicitly call 
devm_backlight_device_unregister() in a wmi_driver .remove callback. I 
confirmed that .remove() is getting called when the device is unbound.


  reply	other threads:[~2021-08-27 16:47 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <DM6PR19MB2636AB267CD321DE40EF324AFA730@DM6PR19MB2636.namprd19.prod.outlook.com>
     [not found] ` <20200731202154.11382-1-ddadap@nvidia.com>
     [not found]   ` <20200731202154.11382-2-ddadap@nvidia.com>
2020-11-10  9:34     ` [PATCH v2 2/2] platform/x86: wmi: fail wmi_driver_register when no GUID is found Hans de Goede
2020-11-12 18:54       ` Daniel Dadap
2021-08-24 22:04       ` [PATCH v3] platform/x86: Add driver for ACPI WMAA EC-based backlight control Daniel Dadap
2021-08-24 22:47         ` Barnabás Pőcze
2021-08-25 16:36           ` Daniel Dadap
2021-08-25 22:26           ` Daniel Dadap
2021-08-27 16:47             ` Daniel Dadap [this message]
2021-08-27 17:12               ` Daniel Dadap
2021-08-25  9:05         ` Andy Shevchenko
2021-08-25 16:47           ` Daniel Dadap
2021-08-25 22:06             ` Thomas Weißschuh
2021-08-25 22:28               ` Daniel Dadap
2021-08-26 13:35             ` Andy Shevchenko
2021-08-26 15:39               ` Daniel Dadap
2021-08-31 22:49                 ` [PATCH v4] " Daniel Dadap
2021-09-01  9:25                   ` Thomas Weißschuh
2021-09-02  2:12                     ` Daniel Dadap
2021-09-02 10:19                       ` Thomas Weißschuh
2021-09-02 20:15                         ` Daniel Dadap
2021-09-02 20:31                           ` Hans de Goede
2021-09-02 21:47                             ` [PATCH v5] " Daniel Dadap
2021-09-02 23:20                               ` Thomas Weißschuh
2021-09-03  0:22                                 ` Daniel Dadap
2021-09-03  8:14                                   ` Andy Shevchenko
2021-09-03 17:55                                     ` Daniel Dadap
2021-09-03  0:38                                 ` [PATCH v6] " Daniel Dadap
2021-09-13  9:01                                   ` Hans de Goede
2021-09-20 13:29                                     ` Pali Rohár
2021-09-20 13:33                                       ` Hans de Goede
2021-09-20 13:51                                         ` Pali Rohár
2021-09-20 17:34                                           ` Daniel Dadap
2021-09-20 17:55                                             ` Pali Rohár
2021-09-20 19:38                                               ` Daniel Dadap
2021-09-20 19:52                                                 ` Pali Rohár
2021-09-21 13:53                                           ` Hans de Goede
2021-09-21 14:02                                             ` Pali Rohár
2021-09-21 14:29                                             ` Daniel Dadap
2021-09-21 14:58                                               ` Hans de Goede
2021-09-27 20:23                                                 ` [PATCH 1/2] platform/x86: Remove "WMAA" from identifier names in wmaa-backlight-wmi.c Daniel Dadap
2021-09-27 20:23                                                   ` [PATCH 2/2] platform/x86: Rename wmaa-backlight-wmi to nvidia-wmi-ec-backlight Daniel Dadap
2021-10-11 13:00                                                   ` [PATCH 1/2] platform/x86: Remove "WMAA" from identifier names in wmaa-backlight-wmi.c Hans de Goede
2021-09-27 22:52                                                 ` [PATCH v6] platform/x86: Add driver for ACPI WMAA EC-based backlight control Daniel Dadap
2021-09-02  9:28                     ` [PATCH v4] " Andy Shevchenko
2021-09-02  9:33                       ` Thomas Weißschuh
2021-09-02  9:36                         ` Andy Shevchenko
2021-09-01 15:57                   ` Andy Shevchenko
2021-09-01 23:12                     ` Aaron Plattner
2021-09-02  2:37                     ` Daniel Dadap
2021-09-02  9:35                       ` Andy Shevchenko
2021-09-02 20:15                         ` Daniel Dadap
2021-09-03  8:10                           ` Andy Shevchenko
2021-09-02 15:38                   ` Hans de Goede

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