[RFC 0/2] Add PM_QOS_MEMORY_BANDWIDTH class

From: Tomeu Vizoso
Date: Tue Aug 05 2014 - 10:35:53 EST


Hi,

I need a way for device drivers to register their needs of memory bandwidth so
the optimal frequency for the memory bus clock can be set.

Adding one more pm_qos class and a PM_QOS_SUM class type seems to accomplish
that neatly, so I'm asking for comments on these very simple patches.

The patch to drm/tegra isn't really functional because the EMC clock
implementation [0] hasn't been merged yet, and I'm not posting an
implementation of a notification listener because in my platform that would be
the EMC driver which is still under discussion as well.

This will be most useful once we have per-user clock constraints [1], so the
EMC driver can set one more floor frequency that together with the other
constraints would lead to the effective rate of the memory bus.

Thanks,

Tomeu

[0] http://article.gmane.org/gmane.linux.kernel/1744817
[1] http://article.gmane.org/gmane.linux.kernel/1760039

Tomeu Vizoso (2):
PM / QoS: Add PM_QOS_MEMORY_BANDWIDTH class
drm/tegra: Request memory bandwidth for the display controller

drivers/gpu/drm/tegra/dc.c | 11 +++++++++++
drivers/gpu/drm/tegra/drm.h | 2 ++
include/linux/pm_qos.h | 5 ++++-
kernel/power/qos.c | 27 ++++++++++++++++++++++++++-
4 files changed, 43 insertions(+), 2 deletions(-)

--
1.9.3

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