[PATCH v2 00/34] component: Make into an aggregate bus
Andrzej Hajda
andrzej.hajda at gmail.com
Thu Oct 7 12:33:41 UTC 2021
On 07.10.2021 13:22, Andy Shevchenko wrote:
>
>
> On Wednesday, October 6, 2021, Stephen Boyd <swboyd at chromium.org
> <mailto:swboyd at chromium.org>> wrote:
>
> This series is from discussion we had on reordering the device lists for
> drm shutdown paths[1]. I've introduced an 'aggregate' bus that we put
> the aggregate device onto and then we probe the aggregate device once
> all the components are probed and call component_add(). The probe/remove
> hooks are where the bind/unbind calls go, and then a shutdown hook is
> added that can be used to shutdown the drm display pipeline at the right
> time.
>
> This works for me on my sc7180 board. I no longer get a warning from i2c
> at shutdown that we're trying to make an i2c transaction after the i2c
> bus has been shutdown. There's more work to do on the msm drm driver to
> extract component device resources like clks, regulators, etc. out of
> the component bind function into the driver probe but I wanted to move
> everything over now in other component drivers before tackling that
> problem.
>
> I'll definitely be sending a v3 so this is partially a request for
> testing to shake out any more problems. Tested-by tags would be
> appreciated,
> and Acked-by/Reviewed-by tags too. I sent this to gregkh which may be
> incorrect but I don't know what better tree to send it all through.
> Maybe drm?
>
> I'll be faster at resending this next time, sorry for the long delay!
>
>
> Yet another avoidance of mathematically proven device dependency graph...
>
>
> Can we actually find and ask a mathematician to look into the problem
> and suggest real solution instead of all these ugly hacks: deferred
> probe (ugliest hack, how it even came into kernel?), component
> framework, custom approaches on how to see if devices are in the system
> (ASoC hack).
Master of Science in Math is OK? :)
The solution is simple - topological sort - this is what PM device list
does, but it is possible only if there are no circular dependencies.
And in this case we have circular dependency.
In such case the solution in case of initialization is to split it to
two phases - probe/bind (component framework), probe/attach (DSI bus)
and it works. But PM still relies on topological sort. To make PM
working with circular deps you can try to extend PM somehow (maybe
replace list of devices with list of pairs (device, phase) ??? ), or to
add notifiers to frameworks allowing providers to informs its consumers
about state change. The latter approach I have advertised several times,
even on OSS.
[1]: https://static.sched.com/hosted_files/osseu18/0f/deferred_problem.pdf
[2]: https://lwn.net/Articles/625454/
Regards
Andrzej
>
> Changes since v1
> (https://lore.kernel.org/r/20210520002519.3538432-1-swboyd@chromium.org
> <https://lore.kernel.org/r/20210520002519.3538432-1-swboyd@chromium.org>):
> - Use devlink to connect components to the aggregate device
> - Don't set the registering device as a parent of the aggregate device
> - New patch for bind_component/unbind_component ops that takes the
> aggregate device
> - Convert all drivers in the tree to use the aggregate driver approach
> - Allow one aggregate driver to be used for multiple aggregate devices
>
> [1]
> https://lore.kernel.org/r/20210508074118.1621729-1-swboyd@chromium.org
> <https://lore.kernel.org/r/20210508074118.1621729-1-swboyd@chromium.org>
>
> Stephen Boyd (34):
> component: Introduce struct aggregate_device
> component: Introduce the aggregate bus_type
> component: Move struct aggregate_device out to header file
> drm/msm: Migrate to aggregate driver
> component: Add {bind,unbind}_component() ops that take aggregate
> device
> drm/of: Add a drm_of_aggregate_probe() API
> drm/komeda: Migrate to aggregate driver
> drm/arm/hdlcd: Migrate to aggregate driver
> drm/malidp: Migrate to aggregate driver
> drm/armada: Migrate to aggregate driver
> drm/etnaviv: Migrate to aggregate driver
> drm/kirin: Migrate to aggregate driver
> drm/exynos: Migrate to aggregate driver
> drm/imx: Migrate to aggregate driver
> drm/ingenic: Migrate to aggregate driver
> drm/mcde: Migrate to aggregate driver
> drm/mediatek: Migrate to aggregate driver
> drm/meson: Migrate to aggregate driver
> drm/omap: Migrate to aggregate driver
> drm/rockchip: Migrate to aggregate driver
> drm/sti: Migrate to aggregate driver
> drm/sun4i: Migrate to aggregate driver
> drm/tilcdc: Migrate to aggregate driver
> drm/vc4: Migrate to aggregate driver
> drm/zte: Migrate to aggregate driver
> iommu/mtk: Migrate to aggregate driver
> mei: Migrate to aggregate driver
> power: supply: ab8500: Migrate to aggregate driver
> fbdev: omap2: Migrate to aggregate driver
> sound: hdac: Migrate to aggregate driver
> ASoC: codecs: wcd938x: Migrate to aggregate driver
> component: Get rid of drm_of_component_probe()
> component: Remove component_master_ops and friends
> component: Remove all references to 'master'
>
> Cc: Arnd Bergmann <arnd at arndb.de <mailto:arnd at arndb.de>>
> Cc: Benjamin Gaignard <benjamin.gaignard at linaro.org
> <mailto:benjamin.gaignard at linaro.org>>
> Cc: Chen Feng <puck.chen at hisilicon.com <mailto:puck.chen at hisilicon.com>>
> Cc: Chen-Yu Tsai <wens at csie.org <mailto:wens at csie.org>>
> Cc: Christian Gmeiner <christian.gmeiner at gmail.com
> <mailto:christian.gmeiner at gmail.com>>
> Cc: Chun-Kuang Hu <chunkuang.hu at kernel.org
> <mailto:chunkuang.hu at kernel.org>>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch
> <mailto:daniel.vetter at ffwll.ch>>
> Cc: Emma Anholt <emma at anholt.net <mailto:emma at anholt.net>>
> Cc: Greg Kroah-Hartman <gregkh at linuxfoundation.org
> <mailto:gregkh at linuxfoundation.org>>
> Cc: "Heiko Stübner" <heiko at sntech.de <mailto:heiko at sntech.de>>
> Cc: Inki Dae <inki.dae at samsung.com <mailto:inki.dae at samsung.com>>
> Cc: James Qian Wang (Arm Technology China) <james.qian.wang at arm.com
> <mailto:james.qian.wang at arm.com>>
> Cc: Jaroslav Kysela <perex at perex.cz <mailto:perex at perex.cz>>
> Cc: Joerg Roedel <joro at 8bytes.org <mailto:joro at 8bytes.org>>
> Cc: John Stultz <john.stultz at linaro.org <mailto:john.stultz at linaro.org>>
> Cc: Joonyoung Shim <jy0922.shim at samsung.com
> <mailto:jy0922.shim at samsung.com>>
> Cc: Jyri Sarha <jyri.sarha at iki.fi <mailto:jyri.sarha at iki.fi>>
> Cc: Kai Vehmanen <kai.vehmanen at linux.intel.com
> <mailto:kai.vehmanen at linux.intel.com>>
> Cc: Kyungmin Park <kyungmin.park at samsung.com
> <mailto:kyungmin.park at samsung.com>>
> Cc: Laurent Pinchart <laurent.pinchart at ideasonboard.com
> <mailto:laurent.pinchart at ideasonboard.com>>
> Cc: <linux-fbdev at vger.kernel.org <mailto:linux-fbdev at vger.kernel.org>>
> Cc: <linux-omap at vger.kernel.org <mailto:linux-omap at vger.kernel.org>>
> Cc: <linux-pm at vger.kernel.org <mailto:linux-pm at vger.kernel.org>>
> Cc: Liviu Dudau <liviu.dudau at arm.com <mailto:liviu.dudau at arm.com>>
> Cc: Lucas Stach <l.stach at pengutronix.de <mailto:l.stach at pengutronix.de>>
> Cc: Mark Brown <broonie at kernel.org <mailto:broonie at kernel.org>>
> Cc: Maxime Ripard <mripard at kernel.org <mailto:mripard at kernel.org>>
> Cc: Neil Armstrong <narmstrong at baylibre.com
> <mailto:narmstrong at baylibre.com>>
> Cc: Paul Cercueil <paul at crapouillou.net <mailto:paul at crapouillou.net>>
> Cc: Philipp Zabel <p.zabel at pengutronix.de
> <mailto:p.zabel at pengutronix.de>>
> Cc: "Rafael J. Wysocki" <rafael at kernel.org <mailto:rafael at kernel.org>>
> Cc: Rob Clark <robdclark at gmail.com <mailto:robdclark at gmail.com>>
> Cc: Russell King <linux at armlinux.org.uk <mailto:linux at armlinux.org.uk>>
> Cc: Russell King <linux+etnaviv at armlinux.org.uk
> <mailto:linux+etnaviv at armlinux.org.uk>>
> Cc: Russell King <rmk+kernel at arm.linux.org.uk
> <mailto:rmk+kernel at arm.linux.org.uk>>
> Cc: Sandy Huang <hjc at rock-chips.com <mailto:hjc at rock-chips.com>>
> Cc: Saravana Kannan <saravanak at google.com <mailto:saravanak at google.com>>
> Cc: Sebastian Reichel <sre at kernel.org <mailto:sre at kernel.org>>
> Cc: Seung-Woo Kim <sw0312.kim at samsung.com
> <mailto:sw0312.kim at samsung.com>>
> Cc: Takashi Iwai <tiwai at suse.com <mailto:tiwai at suse.com>>
> Cc: Tian Tao <tiantao6 at hisilicon.com <mailto:tiantao6 at hisilicon.com>>
> Cc: Tomas Winkler <tomas.winkler at intel.com
> <mailto:tomas.winkler at intel.com>>
> Cc: Tomi Valkeinen <tomba at kernel.org <mailto:tomba at kernel.org>>
> Cc: Will Deacon <will at kernel.org <mailto:will at kernel.org>>
> Cc: Xinliang Liu <xinliang.liu at linaro.org
> <mailto:xinliang.liu at linaro.org>>
> Cc: Xinwei Kong <kong.kongxinwei at hisilicon.com
> <mailto:kong.kongxinwei at hisilicon.com>>
> Cc: Yong Wu <yong.wu at mediatek.com <mailto:yong.wu at mediatek.com>>
>
> drivers/base/component.c | 555 +++++++++++-------
> .../gpu/drm/arm/display/komeda/komeda_drv.c | 20 +-
> drivers/gpu/drm/arm/hdlcd_drv.c | 21 +-
> drivers/gpu/drm/arm/malidp_drv.c | 21 +-
> drivers/gpu/drm/armada/armada_drv.c | 23 +-
> drivers/gpu/drm/drm_drv.c | 2 +-
> drivers/gpu/drm/drm_of.c | 20 +-
> drivers/gpu/drm/etnaviv/etnaviv_drv.c | 20 +-
> drivers/gpu/drm/exynos/exynos_drm_drv.c | 21 +-
> .../gpu/drm/hisilicon/kirin/kirin_drm_drv.c | 20 +-
> drivers/gpu/drm/imx/imx-drm-core.c | 20 +-
> drivers/gpu/drm/ingenic/ingenic-drm-drv.c | 24 +-
> drivers/gpu/drm/mcde/mcde_drv.c | 23 +-
> drivers/gpu/drm/mediatek/mtk_drm_drv.c | 20 +-
> drivers/gpu/drm/meson/meson_drv.c | 21 +-
> drivers/gpu/drm/msm/msm_drv.c | 46 +-
> drivers/gpu/drm/omapdrm/dss/dss.c | 17 +-
> drivers/gpu/drm/rockchip/rockchip_drm_drv.c | 20 +-
> drivers/gpu/drm/sti/sti_drv.c | 20 +-
> drivers/gpu/drm/sun4i/sun4i_drv.c | 26 +-
> drivers/gpu/drm/tilcdc/tilcdc_drv.c | 28 +-
> drivers/gpu/drm/vc4/vc4_drv.c | 20 +-
> drivers/gpu/drm/zte/zx_drm_drv.c | 20 +-
> drivers/iommu/mtk_iommu.c | 14 +-
> drivers/iommu/mtk_iommu.h | 6 +-
> drivers/iommu/mtk_iommu_v1.c | 14 +-
> drivers/misc/mei/hdcp/mei_hdcp.c | 22 +-
> drivers/power/supply/ab8500_charger.c | 22 +-
> drivers/video/fbdev/omap2/omapfb/dss/dss.c | 20 +-
> include/drm/drm_of.h | 9 +-
> include/linux/component.h | 92 ++-
> sound/hda/hdac_component.c | 21 +-
> sound/soc/codecs/wcd938x.c | 20 +-
> 33 files changed, 780 insertions(+), 488 deletions(-)
>
>
> base-commit: e4e737bb5c170df6135a127739a9e6148ee3da82
> --
> https://chromeos.dev <https://chromeos.dev>
>
>
>
> --
> With Best Regards,
> Andy Shevchenko
>
>
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