All available downstream ports - physical and logical - are exposed for
each MST device. They are listed in /dev/, following the same naming
scheme as SST devices by appending an incremental ID.
Although all downstream ports are exposed, only some will work as
expected. Consider the following topology:
+---------+
| ASIC |
+---------+
Conn-0|
|
+----v----+
+----| MST HUB |----+
| +---------+ |
| |
|Port-1 Port-2|
+-----v-----+ +-----v-----+
| MST | | SST |
| Display | | Display |
+-----------+ +-----------+
|Port-1
x
MST Path | MST Device
----------+----------------------------------
sst:0 | MST Hub
mst:0-1 | MST Display
mst:0-1-1 | MST Display's disconnected DP out
mst:0-1-8 | MST Display's internal sink
mst:0-2 | SST Display
On certain MST displays, the upstream physical port will ACK DPCD reads.
However, reads on the local logical port to the internal sink will
*NAK*. i.e. reading mst:0-1 ACKs, but mst:0-1-8 NAKs.
There may also be duplicates. Some displays will return the same GUID
when reading DPCD from both mst:0-1 and mst:0-1-8.
There are some device-dependent behavior as well. The MST hub used
during testing will actually *ACK* read requests on a disconnected
physical port, whereas the MST displays will NAK.
In light of these discrepancies, it's simpler to expose all downstream
ports - both physical and logical - and let the user decide what to use.
v3 changes:
* Change WARN_ON_ONCE -> DRM_ERROR on dpcd read errors
* Docstring and cosmetic fixes
v2 changes:
Moved remote aux device (un)registration to new mst connector late
register and early unregister helpers. Drivers should call these from
their own mst connector function hooks.
This is to solve an issue during driver unload, where mst connector
devices are unregistered before the remote aux devices are. In a setup
where aux devices are created as children of connector devices, the aux
device would be removed too early, and uncleanly. Doing so in
early_unregister solves this issue, as that is called before connector
unregistration.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Leo Li <sunpeng.li@amd.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190723232808.28128-3-sunpeng.li@amd.com
The mipi_dbi helper is missing a dependency on DRM_KMS_HELPER and putting
that in revealed this problem:
drivers/video/fbdev/Kconfig:12:error: recursive dependency detected!
drivers/video/fbdev/Kconfig:12: symbol FB is selected by DRM_KMS_FB_HELPER
drivers/gpu/drm/Kconfig:75: symbol DRM_KMS_FB_HELPER depends on DRM_KMS_HELPER
drivers/gpu/drm/Kconfig:69: symbol DRM_KMS_HELPER is selected by TINYDRM_MIPI_DBI
drivers/gpu/drm/tinydrm/Kconfig:11: symbol TINYDRM_MIPI_DBI is selected by TINYDRM_HX8357D
drivers/gpu/drm/tinydrm/Kconfig:15: symbol TINYDRM_HX8357D depends on BACKLIGHT_CLASS_DEVICE
drivers/video/backlight/Kconfig:144: symbol BACKLIGHT_CLASS_DEVICE is selected by FB_BACKLIGHT
drivers/video/fbdev/Kconfig:187: symbol FB_BACKLIGHT depends on FB
A symbol that selects DRM_KMS_HELPER can not depend on
BACKLIGHT_CLASS_DEVICE. The reason for this is that DRM_KMS_FB_HELPER
selects FB instead of depending on it.
The tinydrm drivers have somehow gotten away with depending on
BACKLIGHT_CLASS_DEVICE because DRM_TINYDRM selects DRM_KMS_HELPER and the
drivers depend on that symbol.
An audit shows that all DRM drivers that select DRM_KMS_HELPER and use
BACKLIGHT_CLASS_DEVICE, selects it:
DRM_TILCDC, DRM_GMA500, DRM_SHMOBILE, DRM_NOUVEAU, DRM_FSL_DCU,
DRM_I915, DRM_RADEON, DRM_AMDGPU, DRM_PARADE_PS8622
Documentation/kbuild/kconfig-language.txt has a note regarding select:
1. 'select should be used with care since it doesn't visit dependencies.'
This is not a problem since BACKLIGHT_CLASS_DEVICE doesn't have any
dependencies.
2. 'In general use select only for non-visible symbols'
BACKLIGHT_CLASS_DEVICE is user visible.
The real solution to this would be to have DRM_KMS_FB_HELPER depend on the
user visible symbol FB. That is a can of worms I'm not willing to tackle.
I fear that such a change will result in me handling difficult fallouts
for the next weeks. So I'm following DRM suite here.
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: David Lechner <david@lechnology.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190722104312.16184-7-noralf@tronnes.org
Split struct mipi_dbi into an interface part and a display pipeline part.
The interface part can be used by drivers that need to initialize the
controller, but that won't upload the framebuffer over this interface.
MIPI DBI supports 3 interface types:
- A. Motorola 6800 type parallel bus
- B. Intel 8080 type parallel bus
- C. SPI type with 3 options:
I've embedded the SPI type specifics in the mipi_dbi struct to avoid
adding unnecessary complexity. If more interface types will be supported
in the future, the type specifics might have to be split out.
Rename functions to match the new struct mipi_dbi_dev:
- drm_to_mipi_dbi() -> drm_to_mipi_dbi_dev().
- mipi_dbi_init*() -> mipi_dbi_dev_init*().
Cc: Eric Anholt <eric@anholt.net>
Cc: David Lechner <david@lechnology.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Acked-by: David Lechner <david@lechnology.com>
Acked-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20190722104312.16184-5-noralf@tronnes.org
struct mipi_dbi is going to be split into an interface part and a display
pipeline part. The interface part can be used by drivers that need to
initialize the controller, but that won't upload the framebuffer over
this interface.
tinydrm uses the variable name 'mipi' but this is not a good name since
MIPI refers to a lot of standards. This patch changes the variable name
to 'dbidev' where it refers to the pipeline part of struct mipi_dbi.
Cc: Eric Anholt <eric@anholt.net>
Cc: David Lechner <david@lechnology.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Acked-by: David Lechner <david@lechnology.com>
Acked-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20190722104312.16184-4-noralf@tronnes.org
struct mipi_dbi is going to be split into an interface part and a display
pipeline part. The interface part can be used by drivers that need to
initialize the controller, but that won't upload the framebuffer over
this interface.
tinydrm uses the variable name 'mipi' but this is not a good name since
MIPI refers to a lot of standards. This patch changes the variable name
to 'dbi' where it refers to the interface part of struct mipi_dbi.
Functions that use both future parts will have both variables temporarily
pointing to the same structure.
Cc: Eric Anholt <eric@anholt.net>
Cc: David Lechner <david@lechnology.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Acked-by: David Lechner <david@lechnology.com>
Acked-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20190722104312.16184-3-noralf@tronnes.org
au1200fb allocates DMA memory using DMA_ATTR_NON_CONSISTENT, but never
calls dma_cache_sync to synchronize the memory between the CPU and the
device. If it was use on a not cache coherent bus that would be fatal,
but as far as I can tell from the naming and the mips platform
implementation it always is used in cache coherent systems. Remove
the DMA_ATTR_NON_CONSISTENT flag, which is a no-op in that case.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Manuel Lauss <manuel.lauss@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190625121321.10197-1-hch@lst.de
The MIPI DBI standard support more pixel formats than what this helper
supports. Add an init function that lets the driver use different
format(s). This avoids open coding mipi_dbi_init() in st7586.
st7586 sets preferred_depth but this is not necessary since it only
supports one format.
v2: Forgot to remove the mipi->rotation assignment in st7586,
mipi_dbi_init_with_formats() handles it.
Cc: David Lechner <david@lechnology.com>
Acked-by: David Lechner <david@lechnology.com>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Tested-by: David Lechner <david@lechnology.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190719155916.62465-11-noralf@tronnes.org
This is only used by mipi-dbi drivers so move it there.
The reason this isn't moved to the SPI subsystem is that it will in a
later patch pass a dummy rx buffer for SPI controllers that need this.
Low memory boards (64MB) can run into a problem allocating such a "large"
contiguous buffer on every transfer after a long up time.
This leaves a very specific use case, so we'll keep the function here.
mipi-dbi will first go through a refactoring though, before this will
be done.
Remove SPI todo entry now that we're done with the tinydrm.ko SPI code.
v2: Drop moving the mipi_dbi_spi_init() declaration (Sam)
Cc: David Lechner <david@lechnology.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: : David Lechner <david@lechnology.com>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190719155916.62465-8-noralf@tronnes.org
Prep work before moving the function to mipi-dbi.
tinydrm_spi_transfer() was made to support one class of drivers in
drivers/staging/fbtft that has not been converted to DRM yet, so strip
away the unused functionality:
- Start byte (header) is not used.
- No driver relies on the automatic 16-bit byte swapping on little endian
machines with SPI controllers only supporting 8 bits per word.
Other changes:
- No need to initialize ret
- No need for the WARN since mipi-dbi only uses 8 and 16 bpw.
- Use spi_message_init_with_transfers()
Cc: David Lechner <david@lechnology.com>
Acked-by: : David Lechner <david@lechnology.com>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190719155916.62465-7-noralf@tronnes.org
spi-bcm2835 can handle >64kB buffers now so there is no need to check
->max_dma_len. The tinydrm_spi_max_transfer_size() max_len argument is
not used by any callers, so not needed.
Then we have the spi_max module parameter. It was added because
staging/fbtft has support for it and there was a report that someone used
it to set a small buffer size to avoid popping on a USB soundcard on a
Raspberry Pi. In hindsight it shouldn't have been added, I should have
waited for it to become a problem first. I don't know it anyone is
actually using it, but since tinydrm_spi_transfer() is being moved to
mipi-dbi, I'm taking the opportunity to remove it. I'll add it back to
mipi-dbi if someone complains.
With that out of the way, spi_max_transfer_size() can be used instead.
The chosen 16kB buffer size for Type C Option 1 (9-bit) interface is
somewhat arbitrary, but a bigger buffer will have a miniscule impact on
transfer speed, so it's probably fine.
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190719155916.62465-6-noralf@tronnes.org
tinydrm drivers announce DRM_MODE_CONNECTOR_VIRTUAL for its SPI drivers.
Use the new SPI connector type instead.
X server will now list the connector as Unknown instead of Virtual:
X.Org X Server 1.19.2
Release Date: 2017-03-02
<...>
[ 53523.905] (II) modeset(0): Output Unknown19-1 has no monitor section
[ 53523.908] (II) modeset(0): EDID for output Unknown19-1
[ 53523.910] (II) modeset(0): Printing probed modes for output Unknown19-1
[ 53523.911] (II) modeset(0): Modeline "320x240"x0.0 0.00 320 320 320 320 240 240 240 240 (0.0 kHz eP)
[ 53523.911] (II) modeset(0): Output Unknown19-1 connected
[ 53523.912] (II) modeset(0): Using exact sizes for initial modes
[ 53523.912] (II) modeset(0): Output Unknown19-1 using initial mode 320x240 +0+0
I won't chase down and fix userspace, but the new connector type will
trickle out to userspace eventually.
v2: Split patch in core and driver changes, expand commit message (Daniel)
Cc: David Lechner <david@lechnology.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: David Lechner <david@lechnology.com>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190719155916.62465-3-noralf@tronnes.org
tinydrm drivers announce DRM_MODE_CONNECTOR_VIRTUAL for its SPI drivers.
Add a SPI connector type to match the actual connector.
X will list the connector as Unknown:
X.Org X Server 1.19.2
Release Date: 2017-03-02
<...>
[ 53523.905] (II) modeset(0): Output Unknown19-1 has no monitor section
[ 53523.908] (II) modeset(0): EDID for output Unknown19-1
[ 53523.910] (II) modeset(0): Printing probed modes for output Unknown19-1
[ 53523.911] (II) modeset(0): Modeline "320x240"x0.0 0.00 320 320 320 320 240 240 240 240 (0.0 kHz eP)
[ 53523.911] (II) modeset(0): Output Unknown19-1 connected
[ 53523.912] (II) modeset(0): Using exact sizes for initial modes
[ 53523.912] (II) modeset(0): Output Unknown19-1 using initial mode 320x240 +0+0
The weston source shows that it will be listed as UNNAMED.
v2: Split patch in core and driver changes, expand commit message (Daniel)
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: David Lechner <david@lechnology.com>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190719155916.62465-2-noralf@tronnes.org
