On 06/24/2013 04:27 PM, David Herrmann wrote: > The SimpleDRM driver binds to simple-framebuffer devices and provides a > DRM/KMS API. It provides only a single CRTC+encoder+connector combination > plus one initial mode. > > Userspace can create one dumb-buffer and attach it to the CRTC. Only if > the buffer is destroyed, a new buffer can be created. The buffer is > directly mapped into user-space, so we have only resources for a single > buffer. Otherwise, shadow buffers plus damage-request would be needed.
> diff --git a/drivers/gpu/drm/simpledrm/Kconfig > b/drivers/gpu/drm/simpledrm/Kconfig > +config DRM_SIMPLEDRM > + tristate "Simple firmware framebuffer DRM driver" > + depends on DRM && !FB_SIMPLE > + help > + SimpleDRM can run on all systems with pre-initialized graphics > + hardware. It uses a framebuffer that was initialized during > + firmware boot. No page-flipping, modesetting or other advanced > + features are available. However, other DRM drivers can be loaded > + later and take over from SimpleDRM if they provide real hardware > + support. > + > + SimpleDRM supports: "simple-framebuffer" DeviceTree objects, x86 VESA > + BIOS Extensions (VBE), EFI framebuffers DT objects, yes. I'm not sure it's quite true to say it actually directly supports VBE or EFI FBs; it's more the code in patch 2/6 that supports those. I guess this is a bit nit-picky of a distinction though. > diff --git a/drivers/gpu/drm/simpledrm/simpledrm_drv.c > b/drivers/gpu/drm/simpledrm/simpledrm_drv.c > +static int parse_dt(struct platform_device *pdev, > + struct simplefb_platform_data *mode) > + strlcpy(mode->format, format, sizeof(mode->format)); Even here, I believe the DT data sticks around so just copying the pointer should be safe. It'd be worth validating that for sure though. I didn't review the DRM stuff here since I'm not at all familiar with DRM.
