Re: [RFC PATCH v2 00/11] Simple QoS for exynos-bus driver using interconnect

["Artur Świgoń" <a.swigon@samsung.com>]

On Wed, 2019-09-25 at 15:12 +0900, Chanwoo Choi wrote:
> Hi,
> 
> On 19. 9. 25. 오후 2:47, Artur Świgoń wrote:
> > Hi,
> > 
> > On Fri, 2019-09-20 at 11:14 +0900, Chanwoo Choi wrote:
> > > Hi Artur,
> > > 
> > > I tried to just build this patch on mainline kernel or linux-next.
> > > But, when I applied them, merge conflict happens. You didn't develop
> > > them on latest version. Please rebase them based on latest mainline kernel.
> > 
> > I developed on top of next-20190918 on which I applied
> > https://patchwork.kernel.org/cover/11149497/ as I mentioned in the cover
> > letter. The dev_pm_qos patches and my RFC have just cleanly rebased together on
> > top of next-20190920. Could you check if you have the dev_pm_qos patches (v5,
> > the version number is missing in this one; link above) and if so, where does the
> > conflict appear?
> 
> I faced on the merge conflict of drivers/devfreq/exynos-bus.c.
> I think that It is not related to to dev_pm_qos patch.

I think that it is actually related to the specific version of dev_pm_qos (v5) that
I used because patch 08/08 of dev_pm_qos series modifies exynos_bus_probe() in
drivers/devfreq/exynos-bus.c (https://patchwork.kernel.org/patch/11149507/).

I will rebase the next RFC (v3) on latest dev_pm_qos patches from Leonard and the
latest Linux-next kernel.

> Maybe, Kamil's patches[1] changed the many things of exynos-bus.c
> If your test branch doesn't contain following patches, 
> you need to rebase your patches based on latest mainline kernel 
> from Linus Torvald.
> [1] https://patchwork.kernel.org/cover/11083663/
> - [RESEND PATCH v5 0/4] add coupled regulators for Exynos5422/5800

Yes, requiring Kamil's patches is one of the changes in this RFC (v2), since they
are already merged.

> Today, I tried to apply these patch again based on latest mainline kernel.
> The merge conflict happen still.
> 
> - merge conflict log
> Applying: devfreq: exynos-bus: Extract exynos_bus_profile_init()
> error: patch failed: drivers/devfreq/exynos-bus.c:334
> error: drivers/devfreq/exynos-bus.c: patch does not apply
> Patch failed at 0001 devfreq: exynos-bus: Extract exynos_bus_profile_init()
> 
> 
> > 
> > > On 19. 9. 20. 오전 10:07, Chanwoo Choi wrote:
> > > > Hi Artur,
> > > > 
> > > > On v1, I mentioned that we need to discuss how to change
> > > > the v2 for this. But, I have not received any reply from you on v1.
> > > > And, without your reply from v1, you just send v2.
> > > > 
> > > > I think that it is not proper development sequence.
> > > > I have spent many times to review your patches
> > > > and also I'll review your patches. You have to take care
> > > > the reply of reviewer and and keep the basic rule
> > > > of mailing contribution for discussion.
> > > > 
> > > > On 19. 9. 19. 오후 11:22, Artur Świgoń wrote:
> > > > > The following patchset adds interconnect[1][2] framework support to the
> > > > > exynos-bus devfreq driver. Extending the devfreq driver with interconnect
> > > > > capabilities started as a response to the issue referenced in [3]. The
> > > > > patches can be subdivided into four logical groups:
> > > > > 
> > > > > (a) Refactoring the existing devfreq driver in order to improve readability
> > > > > and accommodate for adding new code (patches 01--04/11).
> > > > > 
> > > > > (b) Tweaking the interconnect framework to support the exynos-bus use case
> > > > > (patches 05--07/11). Exporting of_icc_get_from_provider() allows us to
> > > > > avoid hardcoding every single graph edge in the DT or driver source, and
> > > > > relaxing the requirement contained in that function removes the need to
> > > > > provide dummy node IDs in the DT. Adjusting the logic in
> > > > > apply_constraints() (drivers/interconnect/core.c) accounts for the fact
> > > > > that every bus is a separate entity and therefore a separate interconnect
> > > > > provider, albeit constituting a part of a larger hierarchy.
> > > > > 
> > > > > (c) Implementing interconnect providers in the exynos-bus devfreq driver
> > > > > and adding required DT properties for one selected platform, namely
> > > > > Exynos4412 (patches 08--09/11). Due to the fact that this aims to be a
> > > > > generic driver for various Exynos SoCs, node IDs are generated dynamically
> > > > > rather than hardcoded. This has been determined to be a simpler approach,
> > > > > but depends on changes described in (b).
> > > > > 
> > > > > (d) Implementing a sample interconnect consumer for exynos-mixer targeted
> > > > > at the issue referenced in [3], again with DT info only for Exynos4412
> > > > > (patches 10--11/11).
> > > > > 
> > > > > Integration of devfreq and interconnect functionalities is achieved by
> > > > > using dev_pm_qos_*() API[5]. All new code works equally well when
> > > > > CONFIG_INTERCONNECT is 'n' (as in exynos_defconfig) in which case all
> > > > > interconnect API functions are no-ops.
> > > > > 
> > > > > This patchset depends on [5].
> > > > > 
> > > > > --- Changes since v1 [6]:
> > > > > * Rebase on [4] (coupled regulators).
> > > > > * Rebase on [5] (dev_pm_qos for devfreq).
> > > > > * Use dev_pm_qos_*() API[5] instead of overriding frequency in
> > > > >   exynos_bus_target().
> > > > > * Use IDR for node ID allocation.
> > > > > * Avoid goto in functions extracted in patches 01 & 02 (cf. patch 04).
> > > > > * Reverse order of multiplication and division in
> > > > >   mixer_set_memory_bandwidth() (patch 11) to avoid integer overflow.
> > > > > 
> > > > > ---
> > > > > Artur Świgoń
> > > > > Samsung R&D Institute Poland
> > > > > Samsung Electronics
> > > > > 
> > > > > ---
> > > > > References:
> > > > > [1] Documentation/interconnect/interconnect.rst
> > > > > [2] Documentation/devicetree/bindings/interconnect/interconnect.txt
> > > > > [3] https://patchwork.kernel.org/patch/10861757/ (original issue)
> > > > > [4] https://patchwork.kernel.org/cover/11083663/ (coupled regulators; merged)
> > > > > [5] https://patchwork.kernel.org/cover/11149497/ (dev_pm_qos for devfreq)
> > > > > [6] https://patchwork.kernel.org/cover/11054417/ (v1 of this RFC)
> > > > > 
> > > > > Artur Świgoń (10):
> > > > >   devfreq: exynos-bus: Extract exynos_bus_profile_init()
> > > > >   devfreq: exynos-bus: Extract exynos_bus_profile_init_passive()
> > > > >   devfreq: exynos-bus: Change goto-based logic to if-else logic
> > > > >   devfreq: exynos-bus: Clean up code
> > > > >   interconnect: Export of_icc_get_from_provider()
> > > > >   interconnect: Relax requirement in of_icc_get_from_provider()
> > > > >   interconnect: Relax condition in apply_constraints()
> > > > >   arm: dts: exynos: Add parents and #interconnect-cells to Exynos4412
> > > > >   devfreq: exynos-bus: Add interconnect functionality to exynos-bus
> > > > >   arm: dts: exynos: Add interconnects to Exynos4412 mixer
> > > > > 
> > > > > Marek Szyprowski (1):
> > > > >   drm: exynos: mixer: Add interconnect support
> > > > > 
> > > > >  .../boot/dts/exynos4412-odroid-common.dtsi    |   1 +
> > > > >  arch/arm/boot/dts/exynos4412.dtsi             |  10 +
> > > > >  drivers/devfreq/exynos-bus.c                  | 319 +++++++++++++-----
> > > > >  drivers/gpu/drm/exynos/exynos_mixer.c         |  71 +++-
> > > > >  drivers/interconnect/core.c                   |  12 +-
> > > > >  include/linux/interconnect-provider.h         |   6 +
> > > > >  6 files changed, 327 insertions(+), 92 deletions(-)
> > > > >