c0c81245da
Currently, no driver support for DDR memory controller (DMC) is present, as a result, no driver is explicitly consuming the ddrphy clock. This means that VPLL1 (parent of ddr clock) will be shutdown if we enable and then disable any child clock of VPLL1 (e.g. SCLK_I2S0_8CH_TX). If VPLL1 is disabled, the whole system will freeze, because the DDR controller will lose its clock. So, it's necessary to prevent VPLL1 from shutting down, by marking the ddrphy4x CLK_IS_CRITICAL. This bug was discovered when I was porting rockchip_i2s_tdm driver to mainline kernel from Rockchip 4.4 kernel. I guess that other Rockchip SoCs without DMC driver may need the same patch. If this applies to other devices, please let us know. Signed-off-by: Yunhao Tian <t123yh@outlook.com> Link: https://lore.kernel.org/r/BYAPR20MB24886765F888A9705CBEB70789E39@BYAPR20MB2488.namprd20.prod.outlook.com [adapted subject, changed to add the clock to the critical list] Signed-off-by: Heiko Stuebner <heiko@sntech.de> |
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| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| 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 | ||
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.