Re: [Nouveau] [PATCH 01/11] drm/fb-helper: do a generic fb_setcmap helper in terms of crtc .gamma_se

On 21/06/17 05:14 PM, Daniel Vetter wrote:

On Wed, Jun 21, 2017 at 04:59:31PM +0900, Michel Dänzer wrote:

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On 21/06/17 04:38 PM, Daniel Vetter wrote:

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On Tue, Jun 20, 2017 at 09:25:25PM +0200, Peter Rosin wrote:

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This makes the redundant fb helpers .load_lut, .gamma_set and .gamma_get
totally obsolete.

I think the gamma_store can end up invalid on error. But the way I read
it, that can happen in drm_mode_gamma_set_ioctl as well, so why should
this pesky legacy fbdev stuff be any better?

drm_fb_helper_save_lut_atomic justs saves the gamma lut for later. However,
it saves it to the gamma_store which should already be up to date with what
.gamma_get would return and is thus a nop. So, zap it.

Removing drm_fb_helper_save_lut_atomic should be a separate patch I
think.
 

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Signed-off-by: Peter Rosin <redacted>

[...]

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@@ -1167,50 +1150,6 @@ void drm_fb_helper_set_suspend_unlocked(struct drm_fb_helper *fb_helper,
 }
 EXPORT_SYMBOL(drm_fb_helper_set_suspend_unlocked);
 
-static int setcolreg(struct drm_crtc *crtc, u16 red, u16 green,
-		     u16 blue, u16 regno, struct fb_info *info)
-{
-	struct drm_fb_helper *fb_helper = info->par;
-	struct drm_framebuffer *fb = fb_helper->fb;
-
-	if (info->fix.visual = FB_VISUAL_TRUECOLOR) {

This case here seems gone, and it was also the pièce de résistance when I
tried tackling fbdev lut support. As far as I understand this stuff we do
not support FB_VISUAL_TRUECOLOR palette, and all that bitshifting here is
pointless. But I'm honestly not really clear.

I think removing this case should also be a separate patch, and I'd very
much prefer that someone with some fbdev-clue would ack it.

No need for anyone with fbdev-clue, just run fbset -i. :)

Adding Bartlomiej and the linux-fbdev list, just in case I'm wrong below.

quoted

fbcon uses a TRUECOLOR visual at depths > 8.

Then I understand even less what exactly this code does ... Should we keep
it?

I think we need it. It updates the entries of info->pseudo_palette,
which is kind of a pseudocolor palette mapping 16 indices to pixel
values to write to the framebuffer.

If the setcolreg hook is removed, the setcmap hook needs to do this instead.


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer