[PATCH 2/4] drm: Add support for ARM's HDLCD controller.

Emil Velikov emil.l.velikov at gmail.com
Sun Aug 16 01:56:33 PDT 2015

Hi Liviu,

On 5 August 2015 at 15:28, Liviu Dudau <Liviu.Dudau at arm.com> wrote:
> The HDLCD controller is a display controller that supports resolutions
> up to 4096x4096 pixels. It is present on various development boards
> produced by ARM Ltd and emulated by the latest Fast Models from the
> company.
I believe there is a unofficial requirement(?) for new drm drivers to
use atomic modesetting. Not 100% sure on this one though. The
following drivers: tegra, msm, rcar-du, i915, and Daniel's blog [1]
[2] cat provide some information on the topic.

The driver seems to has has a bit of dead code guarded by
HDLCD_*_UNDERRUN. Perhaps these macros should become build or runtime
switch(es) ?

Most DRM drivers do not threat dma, bus_error, vsync and/or underrun
interrupts as debug functionality. They are of limited use in this
driver, presently, yet the CONFIG_DEBUG_FS guard seems a bit strange


[1] http://blog.ffwll.ch/2014/11/atomic-modeset-support-for-kms-drivers.html
[2] http://blog.ffwll.ch/2015/01/update-for-atomic-display-updates.html

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