Some questions about DRM(Direct Rendering Manager)

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.

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()?

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.

below is additional comments.

daeinki 쓴 글:

Quoted 9 lines

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.

Quoted 6 lines

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 9 lines

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)

Quoted 6 lines

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 11 lines

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
[email protected]
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

It adds dri-devel at lists.freedesktop.org to this mail thread. Thank you.

2011? 6? 22? ?? 3:04, daeinki <[email protected]>?? ?:

Quoted 55 lines

below is additional comments.

daeinki ? ?:

Quoted 9 lines

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.

Quoted 6 lines

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 9 lines

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)

Quoted 6 lines

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 11 lines

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.

Quoted 5 lines

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel at lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

_______________________________________________
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dri-devel at lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/dri-devel

fwiw, drm_fb_helper_single_fb_probe() calls register_framebuffer() (if that was the question?)

BR,
-R

2011/6/22 InKi Dae <[email protected]>:

Quoted 68 lines

It adds [email protected] to this mail thread. Thank you.

2011년 6월 22일 오후 3:04, daeinki <[email protected]>님의 말:

Quoted 50 lines

below is additional comments.

daeinki 쓴 글:

Quoted 9 lines

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.

Quoted 6 lines

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 9 lines

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)

Quoted 6 lines

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 8 lines

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.

Quoted 9 lines

Quoted 3 lines

Best Regards
Inki Dae.

_______________________________________________
linux-arm-kernel mailing list
[email protected]
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

_______________________________________________
dri-devel mailing list
[email protected]
http://lists.freedesktop.org/mailman/listinfo/dri-devel