Hi
On Wed, Jun 26, 2013 at 10:58 PM, Stephen Warren swarren@wwwdotorg.org wrote:
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_SIMPLEhelpSimpleDRM can run on all systems with pre-initialized graphicshardware. It uses a framebuffer that was initialized duringfirmware boot. No page-flipping, modesetting or other advancedfeatures are available. However, other DRM drivers can be loadedlater and take over from SimpleDRM if they provide real hardwaresupport.SimpleDRM supports: "simple-framebuffer" DeviceTree objects, x86 VESABIOS Extensions (VBE), EFI framebuffersDT 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.
I initially intended to add support for "platform-framebuffer" objects, too. This would make vesafb/... obsolete but I dropped that idea for now. I will fix the Kconfig description.
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.
Yep, indeed, I fixed that.
Thanks! David
I didn't review the DRM stuff here since I'm not at all familiar with DRM.