drm: Initialize a linear gamma table by default

Code stolen from gma500.

This is just a minor bit of safety code that I spotted and figured it
might be useful if we put it into the core. This is to make the
get_gamma ioctl reflect likely reality even before the first set_gamma
ioctl call.

v2 on irc: Extend commit message per Maarten's suggestions.

Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1459331485-28376-2-git-send-email-daniel.vetter@ffwll.ch

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index d2a6d95..37427b2 100644 (file)
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -5139,6 +5139,9 @@ EXPORT_SYMBOL(drm_mode_connector_attach_encoder);
 int drm_mode_crtc_set_gamma_size(struct drm_crtc *crtc,
                                 int gamma_size)
 {
+       uint16_t *r_base, *g_base, *b_base;
+       int i;
+
        crtc->gamma_size = gamma_size;
 
        crtc->gamma_store = kcalloc(gamma_size, sizeof(uint16_t) * 3,
@@ -5148,6 +5151,16 @@ int drm_mode_crtc_set_gamma_size(struct drm_crtc *crtc,
                return -ENOMEM;
        }
 
+       r_base = crtc->gamma_store;
+       g_base = r_base + gamma_size;
+       b_base = g_base + gamma_size;
+       for (i = 0; i < gamma_size; i++) {
+               r_base[i] = i << 8;
+               g_base[i] = i << 8;
+               b_base[i] = i << 8;
+       }
+
+
        return 0;
 }
 EXPORT_SYMBOL(drm_mode_crtc_set_gamma_size);

diff --git a/drivers/gpu/drm/gma500/psb_intel_display.c b/drivers/gpu/drm/gma500/psb_intel_display.c
index 398015b..7b6c849 100644 (file)
--- a/drivers/gpu/drm/gma500/psb_intel_display.c
+++ b/drivers/gpu/drm/gma500/psb_intel_display.c
@@ -491,7 +491,6 @@ void psb_intel_crtc_init(struct drm_device *dev, int pipe,
        struct drm_psb_private *dev_priv = dev->dev_private;
        struct gma_crtc *gma_crtc;
        int i;
-       uint16_t *r_base, *g_base, *b_base;
 
        /* We allocate a extra array of drm_connector pointers
         * for fbdev after the crtc */
@@ -519,16 +518,10 @@ void psb_intel_crtc_init(struct drm_device *dev, int pipe,
        gma_crtc->pipe = pipe;
        gma_crtc->plane = pipe;
 
-       r_base = gma_crtc->base.gamma_store;
-       g_base = r_base + 256;
-       b_base = g_base + 256;
        for (i = 0; i < 256; i++) {
                gma_crtc->lut_r[i] = i;
                gma_crtc->lut_g[i] = i;
                gma_crtc->lut_b[i] = i;
-               r_base[i] = i << 8;
-               g_base[i] = i << 8;
-               b_base[i] = i << 8;
 
                gma_crtc->lut_adj[i] = 0;
        }