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authorDave Airlie <airlied@redhat.com>2022-03-04 13:41:52 +1000
committerDave Airlie <airlied@redhat.com>2022-03-04 13:41:57 +1000
commitc9e9ce0b6f85ac330adee912745048a0af5f315d (patch)
treeac5475f48d638f63fc8c1fee1c5d48d2a6d64c33 /Documentation
parentf298a2b94c7bca7f664b99d374cf3e5d79bf9327 (diff)
parent701920ca9822eb63b420b3bcb627f2c1ec759903 (diff)
Merge tag 'drm-misc-next-2022-03-03' of git://anongit.freedesktop.org/drm/drm-misc into drm-next
drm-misc-next for v5.18: UAPI Changes: Cross-subsystem Changes: - Improve performance of some fbdev ops, in some cases up to 6x faster. Core Changes: - Some small DP fixes. - Find panels in subnodes of OF devices, and add of_get_drm_panel_display_mode to retrieve mode. - Add drm_object_property_get_default_value and use it for resetting zpos in plane state reset, removing the need for individual drivers to do it. - Same for color encoding and color range props. - Update panic handling todo doc. - Add todo that format conversion helpers should be sped up similarly to fbdev ops. Driver Changes: - Add panel orientation property to simpledrm for quirked panels. - Assorted small fixes to tiny/repaper, nouveau, stm, omap, ssd130x. - Add crc support to stm/ltdc. - Add MIPI DBI compatible SPI driver - Assorted small fixes to tiny panels and bridge drivers. - Add AST2600 support to aspeed. Signed-off-by: Dave Airlie <airlied@redhat.com> From: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/48fabd78-ade9-f80b-c724-13726c7be69e@linux.intel.com
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml126
-rw-r--r--Documentation/gpu/todo.rst47
2 files changed, 162 insertions, 11 deletions
diff --git a/Documentation/devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml b/Documentation/devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml
new file mode 100644
index 000000000000..f29789994b18
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml
@@ -0,0 +1,126 @@
+# SPDX-License-Identifier: (GPL-2.0-only or BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/panel/panel-mipi-dbi-spi.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MIPI DBI SPI Panel
+
+maintainers:
+ - Noralf Trønnes <noralf@tronnes.org>
+
+description: |
+ This binding is for display panels using a MIPI DBI compatible controller
+ in SPI mode.
+
+ The MIPI Alliance Standard for Display Bus Interface defines the electrical
+ and logical interfaces for display controllers historically used in mobile
+ phones. The standard defines 4 display architecture types and this binding is
+ for type 1 which has full frame memory. There are 3 interface types in the
+ standard and type C is the serial interface.
+
+ The standard defines the following interface signals for type C:
+ - Power:
+ - Vdd: Power supply for display module
+ - Vddi: Logic level supply for interface signals
+ Combined into one in this binding called: power-supply
+ - Interface:
+ - CSx: Chip select
+ - SCL: Serial clock
+ - Dout: Serial out
+ - Din: Serial in
+ - SDA: Bidrectional in/out
+ - D/CX: Data/command selection, high=data, low=command
+ Called dc-gpios in this binding.
+ - RESX: Reset when low
+ Called reset-gpios in this binding.
+
+ The type C interface has 3 options:
+
+ - Option 1: 9-bit mode and D/CX as the 9th bit
+ | Command | the next command or following data |
+ |<0><D7><D6><D5><D4><D3><D2><D1><D0>|<D/CX><D7><D6><D5><D4><D3><D2><D1><D0>|
+
+ - Option 2: 16-bit mode and D/CX as a 9th bit
+ | Command or data |
+ |<X><X><X><X><X><X><X><D/CX><D7><D6><D5><D4><D3><D2><D1><D0>|
+
+ - Option 3: 8-bit mode and D/CX as a separate interface line
+ | Command or data |
+ |<D7><D6><D5><D4><D3><D2><D1><D0>|
+
+ The panel resolution is specified using the panel-timing node properties
+ hactive (width) and vactive (height). The other mandatory panel-timing
+ properties should be set to zero except clock-frequency which can be
+ optionally set to inform about the actual pixel clock frequency.
+
+ If the panel is wired to the controller at an offset specify this using
+ hback-porch (x-offset) and vback-porch (y-offset).
+
+allOf:
+ - $ref: panel-common.yaml#
+ - $ref: /schemas/spi/spi-peripheral-props.yaml#
+
+properties:
+ compatible:
+ items:
+ - enum:
+ - sainsmart18
+ - const: panel-mipi-dbi-spi
+
+ write-only:
+ type: boolean
+ description:
+ Controller is not readable (ie. Din (MISO on the SPI interface) is not
+ wired up).
+
+ dc-gpios:
+ maxItems: 1
+ description: |
+ Controller data/command selection (D/CX) in 4-line SPI mode.
+ If not set, the controller is in 3-line SPI mode.
+
+required:
+ - compatible
+ - reg
+ - panel-timing
+
+unevaluatedProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/gpio/gpio.h>
+
+ spi {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ display@0{
+ compatible = "sainsmart18", "panel-mipi-dbi-spi";
+ reg = <0>;
+ spi-max-frequency = <40000000>;
+
+ dc-gpios = <&gpio 24 GPIO_ACTIVE_HIGH>;
+ reset-gpios = <&gpio 25 GPIO_ACTIVE_HIGH>;
+ write-only;
+
+ backlight = <&backlight>;
+
+ width-mm = <35>;
+ height-mm = <28>;
+
+ panel-timing {
+ hactive = <160>;
+ vactive = <128>;
+ hback-porch = <0>;
+ vback-porch = <0>;
+ clock-frequency = <0>;
+ hfront-porch = <0>;
+ hsync-len = <0>;
+ vfront-porch = <0>;
+ vsync-len = <0>;
+ };
+ };
+ };
+
+...
diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst
index 7bf7f2111696..127e76ee0b2d 100644
--- a/Documentation/gpu/todo.rst
+++ b/Documentation/gpu/todo.rst
@@ -241,6 +241,28 @@ Contact: Thomas Zimmermann <tzimmermann@suse.de>, Daniel Vetter
Level: Advanced
+Benchmark and optimize blitting and format-conversion function
+--------------------------------------------------------------
+
+Drawing to dispay memory quickly is crucial for many applications'
+performance.
+
+On at least x86-64, sys_imageblit() is significantly slower than
+cfb_imageblit(), even though both use the same blitting algorithm and
+the latter is written for I/O memory. It turns out that cfb_imageblit()
+uses movl instructions, while sys_imageblit apparently does not. This
+seems to be a problem with gcc's optimizer. DRM's format-conversion
+helpers might be subject to similar issues.
+
+Benchmark and optimize fbdev's sys_() helpers and DRM's format-conversion
+helpers. In cases that can be further optimized, maybe implement a different
+algorithm. For micro-optimizations, use movl/movq instructions explicitly.
+That might possibly require architecture-specific helpers (e.g., storel()
+storeq()).
+
+Contact: Thomas Zimmermann <tzimmermann@suse.de>
+
+Level: Intermediate
drm_framebuffer_funcs and drm_mode_config_funcs.fb_create cleanup
-----------------------------------------------------------------
@@ -475,8 +497,12 @@ This is a really varied tasks with lots of little bits and pieces:
achieved by using an IPI to the local processor.
* There's a massive confusion of different panic handlers. DRM fbdev emulation
- helpers have one, but on top of that the fbcon code itself also has one. We
- need to make sure that they stop fighting over each another.
+ helpers had their own (long removed), but on top of that the fbcon code itself
+ also has one. We need to make sure that they stop fighting over each other.
+ This is worked around by checking ``oops_in_progress`` at various entry points
+ into the DRM fbdev emulation helpers. A much cleaner approach here would be to
+ switch fbcon to the `threaded printk support
+ <https://lwn.net/Articles/800946/>`_.
* ``drm_can_sleep()`` is a mess. It hides real bugs in normal operations and
isn't a full solution for panic paths. We need to make sure that it only
@@ -488,16 +514,15 @@ This is a really varied tasks with lots of little bits and pieces:
even spinlocks (because NMI and hardirq can panic too). We need to either
make sure to not call such paths, or trylock everything. Really tricky.
-* For the above locking troubles reasons it's pretty much impossible to
- attempt a synchronous modeset from panic handlers. The only thing we could
- try to achive is an atomic ``set_base`` of the primary plane, and hope that
- it shows up. Everything else probably needs to be delayed to some worker or
- something else which happens later on. Otherwise it just kills the box
- harder, prevent the panic from going out on e.g. netconsole.
+* A clean solution would be an entirely separate panic output support in KMS,
+ bypassing the current fbcon support. See `[PATCH v2 0/3] drm: Add panic handling
+ <https://lore.kernel.org/dri-devel/20190311174218.51899-1-noralf@tronnes.org/>`_.
-* There's also proposal for a simplied DRM console instead of the full-blown
- fbcon and DRM fbdev emulation. Any kind of panic handling tricks should
- obviously work for both console, in case we ever get kmslog merged.
+* Encoding the actual oops and preceding dmesg in a QR might help with the
+ dread "important stuff scrolled away" problem. See `[RFC][PATCH] Oops messages
+ transfer using QR codes
+ <https://lore.kernel.org/lkml/1446217392-11981-1-git-send-email-alexandru.murtaza@intel.com/>`_
+ for some example code that could be reused.
Contact: Daniel Vetter