From: Thomas Zimmermann <tzimmermann@suse.de>
To: daniel@ffwll.ch, airlied@linux.ie, mripard@kernel.org,
maarten.lankhorst@linux.intel.com, noralf@tronnes.org,
drawat.floss@gmail.com, airlied@redhat.com, kraxel@redhat.com,
david@lechnology.com, sam@ravnborg.org, javierm@redhat.com,
kernel@amanoeldawod.com, dirty.ice.hu@gmail.com,
michael+lkml@stapelberg.ch, aros@gmx.com,
joshua@stroblindustries.com, arnd@arndb.de
Cc: dri-devel@lists.freedesktop.org, linux-hyperv@vger.kernel.org,
virtualization@lists.linux-foundation.org,
Thomas Zimmermann <tzimmermann@suse.de>
Subject: [PATCH 9/9] drm: Clarify semantics of struct drm_mode_config.{min,max}_{width,height}
Date: Fri, 22 Oct 2021 15:28:29 +0200 [thread overview]
Message-ID: <20211022132829.7697-10-tzimmermann@suse.de> (raw)
In-Reply-To: <20211022132829.7697-1-tzimmermann@suse.de>
Add additional information on the semantics of the size fields in
struct drm_mode_config. Also add a TODO to review all driver for
correct usage of these fields.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
Documentation/gpu/todo.rst | 15 +++++++++++++++
include/drm/drm_mode_config.h | 13 +++++++++++++
2 files changed, 28 insertions(+)
diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst
index 60d1d7ee0719..f4e1d72149f7 100644
--- a/Documentation/gpu/todo.rst
+++ b/Documentation/gpu/todo.rst
@@ -463,6 +463,21 @@ Contact: Thomas Zimmermann <tzimmermann@suse.de>, Christian König, Daniel Vette
Level: Intermediate
+Review all drivers for setting struct drm_mode_config.{max_width,max_height} correctly
+--------------------------------------------------------------------------------------
+
+The values in struct drm_mode_config.{max_width,max_height} describe the
+maximum supported framebuffer size. It's the virtual screen size, but many
+drivers treat it like limitations of the physical resolution.
+
+The maximum width depends on the hardware's maximum scanline pitch. The
+maximum height depends on the amount of addressable video memory. Review all
+drivers to initialize the fields to the correct values.
+
+Contact: Thomas Zimmermann <tzimmermann@suse.de>
+
+Level: Intermediate
+
Core refactorings
=================
diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
index 48b7de80daf5..91ca575a78de 100644
--- a/include/drm/drm_mode_config.h
+++ b/include/drm/drm_mode_config.h
@@ -359,6 +359,19 @@ struct drm_mode_config_funcs {
* Core mode resource tracking structure. All CRTC, encoders, and connectors
* enumerated by the driver are added here, as are global properties. Some
* global restrictions are also here, e.g. dimension restrictions.
+ *
+ * Framebuffer sizes refer to the virtual screen that can be displayed by
+ * the CRTC. This can be different from the physical resolution programmed.
+ * The minimum width and height, stored in @min_width and @min_height,
+ * describe the smallest size of the framebuffer. It correlates to the
+ * minimum programmable resolution.
+ * The maximum width, stored in @max_width, is typically limited by the
+ * maximum pitch between two adjacent scanlines. The maximum height, stored
+ * in @max_height, is usually only limited by the amount of addressable video
+ * memory. For hardware that has no real maximum, drivers should pick a
+ * reasonable default.
+ *
+ * See also @DRM_SHADOW_PLANE_MAX_WIDTH and @DRM_SHADOW_PLANE_MAX_HEIGHT.
*/
struct drm_mode_config {
/**
--
2.33.0
prev parent reply other threads:[~2021-10-22 13:28 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-22 13:28 [PATCH 0/9] drm/simpledrm: Enable damage clips and virtual screens Thomas Zimmermann
2021-10-22 13:28 ` [PATCH 1/9] drm/format-helper: Export drm_fb_clip_offset() Thomas Zimmermann
2021-10-24 8:25 ` Noralf Trønnes
[not found] ` <YXO+bGIW9sn9Rcfw@ravnborg.org>
2021-11-01 8:43 ` Thomas Zimmermann
2021-10-22 13:28 ` [PATCH 2/9] drm/format-helper: Rework format-helper memcpy functions Thomas Zimmermann
2021-10-24 8:25 ` Noralf Trønnes
2021-10-22 13:28 ` [PATCH 3/9] drm/format-helper: Add destination-buffer pitch to drm_fb_swab() Thomas Zimmermann
2021-10-24 8:33 ` Noralf Trønnes
2021-10-22 13:28 ` [PATCH 4/9] drm/format-helper: Rework format-helper conversion functions Thomas Zimmermann
2021-10-24 11:32 ` Noralf Trønnes
2021-11-01 13:38 ` Thomas Zimmermann
2021-10-22 13:28 ` [PATCH 5/9] drm/format-helper: Streamline blit-helper interface Thomas Zimmermann
2021-10-24 14:59 ` Noralf Trønnes
2021-10-22 13:28 ` [PATCH 6/9] drm/fb-helper: Allocate shadow buffer of surface height Thomas Zimmermann
2021-10-24 15:10 ` Noralf Trønnes
2021-10-22 13:28 ` [PATCH 7/9] drm/simpledrm: Enable FB_DAMAGE_CLIPS property Thomas Zimmermann
2021-10-24 15:20 ` Noralf Trønnes
2021-11-01 8:56 ` Thomas Zimmermann
2021-10-22 13:28 ` [PATCH 8/9] drm/simpledrm: Support virtual screen sizes Thomas Zimmermann
2021-10-22 13:28 ` Thomas Zimmermann [this message]
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