635319a4a7
MediaTek IOMMU-SMI diagram is like below. all the consumer connect with
smi-larb, then connect with smi-common.
M4U
|
smi-common
|
-------------
| | ...
| |
larb1 larb2
| |
vdec venc
When the consumer works, it should enable the smi-larb's power which
also need enable the smi-common's power firstly.
Thus, First of all, use the device link connect the consumer and the
smi-larbs. then add device link between the smi-larb and smi-common.
This patch adds device_link between the consumer and the larbs.
When device_link_add, I add the flag DL_FLAG_STATELESS to avoid calling
pm_runtime_xx to keep the original status of clocks. It can avoid two
issues:
1) Display HW show fastlogo abnormally reported in [1]. At the beggining,
all the clocks are enabled before entering kernel, but the clocks for
display HW(always in larb0) will be gated after clk_enable and clk_disable
called from device_link_add(->pm_runtime_resume) and rpm_idle. The clock
operation happened before display driver probe. At that time, the display
HW will be abnormal.
2) A deadlock issue reported in [2]. Use DL_FLAG_STATELESS to skip
pm_runtime_xx to avoid the deadlock.
Corresponding, DL_FLAG_AUTOREMOVE_CONSUMER can't be added, then
device_link_removed should be added explicitly.
Meanwhile, Currently we don't have a device connect with 2 larbs at the
same time. Disallow this case, print the error log.
[1] https://lore.kernel.org/linux-mediatek/1564213888.22908.4.camel@mhfsdcap03/
[2] https://lore.kernel.org/patchwork/patch/1086569/
Suggested-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Tested-by: Frank Wunderlich <frank-w@public-files.de> # BPI-R2/MT7623
Acked-by: Joerg Roedel <jroedel@suse.de>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
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||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.