Re: Some questions about DRM(Direct Rendering Manager)
From: InKi Dae <hidden>
Date: 2011-06-22 07:50:58
Also in:
dri-devel, linux-arm-kernel
It adds dri-devel@lists.freedesktop.org to this mail thread. Thank you. 2011년 6월 22일 오후 3:04, daeinki [off-list ref]님의 말:
below is additional comments. daeinki 쓴 글:quoted
Hi all, I'm writing Samsung SoC based DRM framework and this one includes FIMD and HDMI driver as hardware dependent modules. and for now, encoder, connector, crtc and fb module has been materialized almost. but I'm contending with framebuffer setting issue(created fb_info should be registered to linux framebuffer through register_framebuffer() or not)as default framebuffer at booting time. at drm_fb_helper_single_fb_probe() of drm_fb_helper.c file, fb_helper's fb_probe callback is called and this one creates new framebuffer and returns a value more then 0 if true. internally, this process creates an fb_info object and drm_framebuffer and then drm_framebuffer would be added to mode_config.fb_list of the drm_device.it's my mistake. return value is 0 if true, nonzero otherwise.quoted
a value returned, new_fb is used to decide that it calls register_framebuffer() or drm_fb_helper_set_par(). at this point, I am confused it's a good way to call register_framebuffer() otherwise drm_fb_helper_set_par(). if register_framebuffer() is called then I guess drm_fb_helper_set_par() or drm_crtc_helper_set_config() should be called somewhere subsequently to apply this one to real hardware because previous process is just for maintaining data logically.(not set up data to h/w) it's a right way to call register_framebuffer() and then drm_fb_helper_set_par() or drm_crtc_helper_set_config()? otherwise just only drm_fb_helper_set_par() or drm_crtc_helper_set_config() ignoring register_framebuffer()? and what is the purpose of using register_framebuffer()?I understood that if fb_probe() callback is fail then fb_info object is registered to linux framebuffer through register_framebuffer() otherwise(if true) hardware configuration would be completed by drm_fb_helper_set_par() so the reason of using register_framebuffer() is that the case of failing fb_probe() callback, it is for drawing on only linux framebuffer. is it right?quoted
In my case, first, register_framebuffer() is called and then if desired default crtc id is matched with drm_fb_helper->crtc_info[0 ~ n].crtc_id, it gets mode_set of drm_fb_helper->crtc_info[n] and then it calls drm_crtc_helper_set_config(mode_set). at this time, all the hardware configurations would be completed. thank you in advance. Best Regards Inki Dae._______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
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