On 17 September 2015 at 19:52, Rob Clark <robdclark at gmail.com> wrote:
> On Wed, Sep 16, 2015 at 5:48 AM, Xinliang Liu <xinliang.liu at linaro.org> > wrote: > > > > > > On 16 September 2015 at 02:25, Rob Herring <robh at kernel.org> wrote: > > Hi Rob, thanks a lot for reply:-) > > > >> On 09/15/2015 04:37 AM, Xinwei Kong wrote: > >> > If you config DRM_HISI_FBDEV optional, this patch will only support > >> > fbdev > >> > mode while also supporting double buffer. > >> > >> This is a lot of duplicated code from CMA fbdev. Is double buffering the > >> only reason why CMA fbdev can't be used or are there some other > >> constraints? > > > > Yes, double buffering is the main reason we rewrite our own fbdev. > > CMA fbdev only create one buffer. But we need at least double buffer for > > running Android with fbdev. > > > >> Double buffering in fbdev has always been a hack, so I'm > >> guessing that is not a feature that should be added here. > >> > > If so, I think it is hard to be accepted for my cma fbdev patch to > support > > multi buffer. > > This early week, I have sent a cma fbdev patch for supporting this. The > > subject is > > "[PATCH] drm/cma-helper: Add multi buffer support for cma fbdev". > > We do have a strong will to support this feature. I described the reason > in > > the patch. Please take a look for me. Thank you very much. > > fwiw, drm_gralloc has support for kms. We do have a plan to replace fbdev with kms. But it take time. > Currently it is expected to be > paired w/ a mesa gpu driver, which might not work for everyone, but I > suppose the display part of it could be extracted out for a > gralloc.kms.so for pure sw rendering.. that might be a better > approach. > Yes, I also think kms should be handle in hwc rather than in gralloc. IMO, gralloc should just handle dma buffer alloc and free. We have a reference hwc implementation. which will handle kms inside it. wiki: https://wiki.linaro.org/BenjaminGaignard/HWComposer_DRM?highlight=%28hwcomposer%2 source code: git://git.linaro.org/people/benjamin.gaignard/hwcomposer.git Cheers, -Xinliang > http://git.android-x86.org/?p=platform/hardware/drm_gralloc.git > > BR, > -R > > > -Xinliang > > > >> Rob > >> > >> > Signed-off-by: Xinliang Liu <xinliang.liu at linaro.org> > >> > Signed-off-by: Xinwei Kong <kong.kongxinwei at hisilicon.com> > >> > Signed-off-by: Andy Green <andy.green at linaro.org> > >> > Signed-off-by: Jiwen Qi <qijiwen at hisilicon.com> > >> > Signed-off-by: Yu Gong <gongyu at hisilicon.com> > >> > --- > >> > drivers/gpu/drm/hisilicon/Kconfig | 13 + > >> > drivers/gpu/drm/hisilicon/Makefile | 3 +- > >> > drivers/gpu/drm/hisilicon/hisi_drm_connector.c | 4 + > >> > drivers/gpu/drm/hisilicon/hisi_drm_drv.c | 9 + > >> > drivers/gpu/drm/hisilicon/hisi_drm_dsi.c | 15 + > >> > drivers/gpu/drm/hisilicon/hisi_drm_fb.h | 5 + > >> > drivers/gpu/drm/hisilicon/hisi_drm_fbdev.c | 395 > >> > +++++++++++++++++++++++++ > >> > drivers/gpu/drm/hisilicon/hisi_drm_fbdev.h | 24 ++ > >> > 8 files changed, 467 insertions(+), 1 deletion(-) > >> > create mode 100644 drivers/gpu/drm/hisilicon/hisi_drm_fbdev.c > >> > create mode 100644 drivers/gpu/drm/hisilicon/hisi_drm_fbdev.h > >> > > > > > > _______________________________________________ > > dri-devel mailing list > > dri-devel at lists.freedesktop.org > > http://lists.freedesktop.org/mailman/listinfo/dri-devel > > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.freedesktop.org/archives/dri-devel/attachments/20150917/92ec451c/attachment-0001.html>
