[0/3] Small improvements to ingenic-drm

Message

Paul Cercueil Sept. 15, 2020, 12:38 p.m. UTC

Hi,

Here are three improvements to the ingenic-drm driver.

Patch 1 adds 30-bit RGB support for the SoCs that support it. Not much
to see here.

Patch 2 is here to allow the pixel clock to be re-set when the SoC's
main PLL changes, which can happen at any time. We get a callback before
and after the PLL clock rate is changed, which allows the ingenic-drm
driver to synchronize the clock rate update with vblank. The
synchronization mechanism is implemented with a mutex. I am not sure it
is the best solution, there may be something better/simpler to do here,
but in practice it works just fine.

Patch 3 adds support for using a reserved memory area as storage space
for GEM buffers. On memory-constrained devices, it is hard to find
contiguous space even for a small 320x240 buffer, and sometimes dumb
buffer allocation from userspace fails with -ENOMEM. Using a reserved
memory area makes sure that there will always be space for our GEM
buffers (provided they fit in the memory area).

Cheers,
-Paul

Paul Cercueil (3):
  drm/ingenic: Add support for 30-bit modes
  drm/ingenic: Reset pixclock rate when parent clock rate changes
  drm/ingenic: Add support for reserved memory

 drivers/gpu/drm/ingenic/ingenic-drm-drv.c | 109 +++++++++++++++++++---
 drivers/gpu/drm/ingenic/ingenic-drm.h     |   1 +
 2 files changed, 99 insertions(+), 11 deletions(-)