From nobody Wed Apr 8 21:17:06 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5F170C433FE for ; Sat, 29 Oct 2022 19:30:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229642AbiJ2TaE (ORCPT ); Sat, 29 Oct 2022 15:30:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33336 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229635AbiJ2TaC (ORCPT ); Sat, 29 Oct 2022 15:30:02 -0400 X-Greylist: delayed 976 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Sat, 29 Oct 2022 12:29:58 PDT Received: from moc6.cz (hosting.moc6.cz [IPv6:2a02:c60:c70:8900::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0BDEE140CE for ; Sat, 29 Oct 2022 12:29:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=moc6.cz; s=mail20201116; h=Message-ID:Subject:Cc:To:From:Date:Reply-To:In-Reply-To; bh=/KZ42D3HakbTGEBmYLFXIwAxUy17kAfEEriya9xR94A=; b=PI3A0ss1I9FqpoZTYN1cM8Pqlm gyf8SayurTBFU91SklIzKzQDvMU/BubynTVmXOqvH3HvWB5XrD3to50VSlCzfhy7skuIQMc7geuvu Bg1WoWqA7i9sXYpDj3239B+0qQwSC2RpObTCjmUtyfbGFmn3DB6pBvnmZtEc1CQSw8u3+xp7fKHmW xzrk2m/zwuDQ6wuw+/Ocu091I7BCTsb9WIHieLucVGZG5s/waUOBnzymCL7p2/m5kUj+49Cfmb/pk IbfKx+LlnS6G4DhglkJ8lx9t0MNSr3jnzkkouyiTL00dcaGXKbYqMKYeib17XZ8oYovwqW0wfhKux 2f+DF/D5Rk7FT0DzxLX0zWUCa2wVC1YW+58/aF5EJ8fUzUeB4kdqdGGasRfVlJEmtvrQpZVaRv10d MLB2IjGkQb7aXZkOzCAD9K00HwUdlUtC5ozBqCa2P5deRjm7RtRknRX112aBbgXAkLFNdRDq+H6vk qJQzcIs7iCao17FP288ypEopfQCg4TA9QDlCz1ucFGsVaXDkcYv4uft5PBKMwnmKjxumFILsH+Xhc 4Zw/nSVSYRcQVX7e28YdcDQBebcjfU1WA9rHo3OjmAI/3PuuxScdWvwmzZ9OAYq1woGB55yTQekd5 UZKFq3qAZwgQxc64kt0GyFWueAXvF6BI57eNlok9Y=; Received: from Debian-exim by moc6.cz with local (Exim 4.94.2) (envelope-from ) authenticated: Debian-exim id 1oorGu-000siT-5T; Sat, 29 Oct 2022 21:13:32 +0200 Date: Sat, 29 Oct 2022 21:13:32 +0200 From: Filip Moc To: Harry Wentland , Leo Li , Rodrigo Siqueira Cc: Alex Deucher , Christian =?iso-8859-1?Q?K=F6nig?= , "Pan, Xinhui" , David Airlie , Daniel Vetter , amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: [PATCH] drm/amd/display: add parameter backlight_min Message-ID: MIME-Version: 1.0 Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" There are some devices on which amdgpu won't allow user to set brightness to sufficiently low values even though the hardware would support it just fine. This usually happens in two cases when either configuration of brightness levels via ACPI/ATIF is not available and amdgpu falls back to defaults (currently 12 for minimum level) which may be too high for some devices or even the configuration via ATIF is available but the minimum brightness level provided by the manufacturer is set to unreasonably high value. In either case user can use this new module parameter to adjust the minimum allowed backlight brightness level. Link: https://bugzilla.kernel.org/show_bug.cgi?id=3D203439 Signed-off-by: Filip Moc Reviewed-by: Harry Wentland --- drivers/gpu/drm/amd/amdgpu/amdgpu.h | 3 +++ drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 15 +++++++++++++++ drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 15 +++++++++++++++ 3 files changed, 33 insertions(+) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdg= pu/amdgpu.h index 0e6ddf05c23c..c5445402c49d 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h @@ -200,6 +200,9 @@ extern uint amdgpu_dc_debug_mask; extern uint amdgpu_dc_visual_confirm; extern uint amdgpu_dm_abm_level; extern int amdgpu_backlight; +#ifdef CONFIG_DRM_AMD_DC +extern int amdgpu_backlight_override_min[]; +#endif extern struct amdgpu_mgpu_info mgpu_info; extern int amdgpu_ras_enable; extern uint amdgpu_ras_mask; diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/= amdgpu/amdgpu_drv.c index 16f6a313335e..f2fb549ac52f 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c @@ -43,6 +43,7 @@ #include "amdgpu_irq.h" #include "amdgpu_dma_buf.h" #include "amdgpu_sched.h" +#include "amdgpu_dm.h" #include "amdgpu_fdinfo.h" #include "amdgpu_amdkfd.h" =20 @@ -853,6 +854,20 @@ int amdgpu_backlight =3D -1; MODULE_PARM_DESC(backlight, "Backlight control (0 =3D pwm, 1 =3D aux, -1 a= uto (default))"); module_param_named(backlight, amdgpu_backlight, bint, 0444); =20 +/** + * DOC: backlight_min (array of int) + * Override minimum allowed backlight brightness signal (per display). + * Must be less than the maximum brightness signal. + * Negative value means no override. + * + * Defaults to all -1 (no override on any display). + */ +#ifdef CONFIG_DRM_AMD_DC +int amdgpu_backlight_override_min[AMDGPU_DM_MAX_NUM_EDP] =3D {[0 ... (AMDG= PU_DM_MAX_NUM_EDP-1)] =3D -1}; +MODULE_PARM_DESC(backlight_min, "Override minimum backlight brightness sig= nal (0..max-1, -1 =3D no override (default))"); +module_param_array_named(backlight_min, amdgpu_backlight_override_min, int= , NULL, 0444); +#endif + /** * DOC: tmz (int) * Trusted Memory Zone (TMZ) is a method to protect data being written diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gp= u/drm/amd/display/amdgpu_dm/amdgpu_dm.c index eb4ce7216104..e2c36ba93d05 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -3911,6 +3911,21 @@ static void amdgpu_dm_update_backlight_caps(struct a= mdgpu_display_manager *dm, dm->backlight_caps[bl_idx].min_input_signal =3D AMDGPU_DM_DEFAULT_MIN_BAC= KLIGHT; dm->backlight_caps[bl_idx].max_input_signal =3D AMDGPU_DM_DEFAULT_MAX_BAC= KLIGHT; #endif + + if (amdgpu_backlight_override_min[bl_idx] >=3D 0) { + if (amdgpu_backlight_override_min[bl_idx] < dm->backlight_caps[bl_idx].m= ax_input_signal) { + DRM_INFO("amdgpu: backlight[%i]: overriding minimum brightness from %i = to %i\n", + bl_idx, + dm->backlight_caps[bl_idx].min_input_signal, + amdgpu_backlight_override_min[bl_idx]); + dm->backlight_caps[bl_idx].min_input_signal =3D amdgpu_backlight_overri= de_min[bl_idx]; + } else { + DRM_ERROR("amdgpu: backlight[%i]: minimum brightness override (%i) is n= ot below maximum (%i)\n", + bl_idx, + amdgpu_backlight_override_min[bl_idx], + dm->backlight_caps[bl_idx].max_input_signal); + } + } } =20 static int get_brightness_range(const struct amdgpu_dm_backlight_caps *cap= s, base-commit: d8c03bfe146fd5e081a252cd34f3f12ca0255357 --=20 2.30.2