drm/edid: index CEA/HDMI mode tables using the VIC

Add a dummy entry to CEA/HDMI mode tables so they can be indexed
directly using the VIC, avoiding a +1/-1 dance here and there. This adds
clarity to the error checking for various functions that return the VIC
on success and zero on failure; we can now explicitly check for 0
instead of just subtracting one from an unsigned type.

Also add drm_valid_cea_vic() and drm_valid_hdmi_vic() helpers for
checking valid VICs.

v2: add drm_valid_cea_vic and drm_valid_hdmi_vic helpers (Ville)
    use { } instead of { 0 } for initializing the dummy modes

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1452252111-6439-1-git-send-email-jani.nikula@intel.com
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index c214f1246cb4eaeac86b655af8b44c4dcc7fa5e5..04cb4877fabd89d8e27f16c073912a97e199718e 100644 (file)
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -637,8 +637,12 @@ static const struct minimode extra_modes[] = {
 /*
  * Probably taken from CEA-861 spec.
  * This table is converted from xorg's hw/xfree86/modes/xf86EdidModes.c.
+ *
+ * Index using the VIC.
  */
 static const struct drm_display_mode edid_cea_modes[] = {
+       /* 0 - dummy, VICs start at 1 */
+       { },
        /* 1 - 640x480@60Hz */
        { DRM_MODE("640x480", DRM_MODE_TYPE_DRIVER, 25175, 640, 656,
                   752, 800, 0, 480, 490, 492, 525, 0,
@@ -987,9 +991,11 @@ static const struct drm_display_mode edid_cea_modes[] = {
 };
 
 /*
- * HDMI 1.4 4k modes.
+ * HDMI 1.4 4k modes. Index using the VIC.
  */
 static const struct drm_display_mode edid_4k_modes[] = {
+       /* 0 - dummy, VICs start at 1 */
+       { },
        /* 1 - 3840x2160@30Hz */
        { DRM_MODE("3840x2160", DRM_MODE_TYPE_DRIVER, 297000,
                   3840, 4016, 4104, 4400, 0,
@@ -2548,13 +2554,13 @@ cea_mode_alternate_clock(const struct drm_display_mode *cea_mode)
 static u8 drm_match_cea_mode_clock_tolerance(const struct drm_display_mode *to_match,
                                             unsigned int clock_tolerance)
 {
-       u8 mode;
+       u8 vic;
 
        if (!to_match->clock)
                return 0;
 
-       for (mode = 0; mode < ARRAY_SIZE(edid_cea_modes); mode++) {
-               const struct drm_display_mode *cea_mode = &edid_cea_modes[mode];
+       for (vic = 1; vic < ARRAY_SIZE(edid_cea_modes); vic++) {
+               const struct drm_display_mode *cea_mode = &edid_cea_modes[vic];
                unsigned int clock1, clock2;
 
                /* Check both 60Hz and 59.94Hz */
@@ -2566,7 +2572,7 @@ static u8 drm_match_cea_mode_clock_tolerance(const struct drm_display_mode *to_m
                        continue;
 
                if (drm_mode_equal_no_clocks(to_match, cea_mode))
-                       return mode + 1;
+                       return vic;
        }
 
        return 0;
@@ -2581,13 +2587,13 @@ static u8 drm_match_cea_mode_clock_tolerance(const struct drm_display_mode *to_m
  */
 u8 drm_match_cea_mode(const struct drm_display_mode *to_match)
 {
-       u8 mode;
+       u8 vic;
 
        if (!to_match->clock)
                return 0;
 
-       for (mode = 0; mode < ARRAY_SIZE(edid_cea_modes); mode++) {
-               const struct drm_display_mode *cea_mode = &edid_cea_modes[mode];
+       for (vic = 1; vic < ARRAY_SIZE(edid_cea_modes); vic++) {
+               const struct drm_display_mode *cea_mode = &edid_cea_modes[vic];
                unsigned int clock1, clock2;
 
                /* Check both 60Hz and 59.94Hz */
@@ -2597,12 +2603,17 @@ u8 drm_match_cea_mode(const struct drm_display_mode *to_match)
                if ((KHZ2PICOS(to_match->clock) == KHZ2PICOS(clock1) ||
                     KHZ2PICOS(to_match->clock) == KHZ2PICOS(clock2)) &&
                    drm_mode_equal_no_clocks_no_stereo(to_match, cea_mode))
-                       return mode + 1;
+                       return vic;
        }
        return 0;
 }
 EXPORT_SYMBOL(drm_match_cea_mode);
 
+static bool drm_valid_cea_vic(u8 vic)
+{
+       return vic > 0 && vic < ARRAY_SIZE(edid_cea_modes);
+}
+
 /**
  * drm_get_cea_aspect_ratio - get the picture aspect ratio corresponding to
  * the input VIC from the CEA mode list
@@ -2612,10 +2623,7 @@ EXPORT_SYMBOL(drm_match_cea_mode);
  */
 enum hdmi_picture_aspect drm_get_cea_aspect_ratio(const u8 video_code)
 {
-       /* return picture aspect ratio for video_code - 1 to access the
-        * right array element
-       */
-       return edid_cea_modes[video_code-1].picture_aspect_ratio;
+       return edid_cea_modes[video_code].picture_aspect_ratio;
 }
 EXPORT_SYMBOL(drm_get_cea_aspect_ratio);
 
@@ -2639,13 +2647,13 @@ hdmi_mode_alternate_clock(const struct drm_display_mode *hdmi_mode)
 static u8 drm_match_hdmi_mode_clock_tolerance(const struct drm_display_mode *to_match,
                                              unsigned int clock_tolerance)
 {
-       u8 mode;
+       u8 vic;
 
        if (!to_match->clock)
                return 0;
 
-       for (mode = 0; mode < ARRAY_SIZE(edid_4k_modes); mode++) {
-               const struct drm_display_mode *hdmi_mode = &edid_4k_modes[mode];
+       for (vic = 1; vic < ARRAY_SIZE(edid_4k_modes); vic++) {
+               const struct drm_display_mode *hdmi_mode = &edid_4k_modes[vic];
                unsigned int clock1, clock2;
 
                /* Make sure to also match alternate clocks */
@@ -2657,7 +2665,7 @@ static u8 drm_match_hdmi_mode_clock_tolerance(const struct drm_display_mode *to_
                        continue;
 
                if (drm_mode_equal_no_clocks(to_match, hdmi_mode))
-                       return mode + 1;
+                       return vic;
        }
 
        return 0;
@@ -2673,13 +2681,13 @@ static u8 drm_match_hdmi_mode_clock_tolerance(const struct drm_display_mode *to_
  */
 static u8 drm_match_hdmi_mode(const struct drm_display_mode *to_match)
 {
-       u8 mode;
+       u8 vic;
 
        if (!to_match->clock)
                return 0;
 
-       for (mode = 0; mode < ARRAY_SIZE(edid_4k_modes); mode++) {
-               const struct drm_display_mode *hdmi_mode = &edid_4k_modes[mode];
+       for (vic = 1; vic < ARRAY_SIZE(edid_4k_modes); vic++) {
+               const struct drm_display_mode *hdmi_mode = &edid_4k_modes[vic];
                unsigned int clock1, clock2;
 
                /* Make sure to also match alternate clocks */
@@ -2689,11 +2697,16 @@ static u8 drm_match_hdmi_mode(const struct drm_display_mode *to_match)
                if ((KHZ2PICOS(to_match->clock) == KHZ2PICOS(clock1) ||
                     KHZ2PICOS(to_match->clock) == KHZ2PICOS(clock2)) &&
                    drm_mode_equal_no_clocks_no_stereo(to_match, hdmi_mode))
-                       return mode + 1;
+                       return vic;
        }
        return 0;
 }
 
+static bool drm_valid_hdmi_vic(u8 vic)
+{
+       return vic > 0 && vic < ARRAY_SIZE(edid_4k_modes);
+}
+
 static int
 add_alternate_cea_modes(struct drm_connector *connector, struct edid *edid)
 {
@@ -2713,16 +2726,16 @@ add_alternate_cea_modes(struct drm_connector *connector, struct edid *edid)
        list_for_each_entry(mode, &connector->probed_modes, head) {
                const struct drm_display_mode *cea_mode = NULL;
                struct drm_display_mode *newmode;
-               u8 mode_idx = drm_match_cea_mode(mode) - 1;
+               u8 vic = drm_match_cea_mode(mode);
                unsigned int clock1, clock2;
 
-               if (mode_idx < ARRAY_SIZE(edid_cea_modes)) {
-                       cea_mode = &edid_cea_modes[mode_idx];
+               if (drm_valid_cea_vic(vic)) {
+                       cea_mode = &edid_cea_modes[vic];
                        clock2 = cea_mode_alternate_clock(cea_mode);
                } else {
-                       mode_idx = drm_match_hdmi_mode(mode) - 1;
-                       if (mode_idx < ARRAY_SIZE(edid_4k_modes)) {
-                               cea_mode = &edid_4k_modes[mode_idx];
+                       vic = drm_match_hdmi_mode(mode);
+                       if (drm_valid_hdmi_vic(vic)) {
+                               cea_mode = &edid_4k_modes[vic];
                                clock2 = hdmi_mode_alternate_clock(cea_mode);
                        }
                }
@@ -2773,17 +2786,17 @@ drm_display_mode_from_vic_index(struct drm_connector *connector,
 {
        struct drm_device *dev = connector->dev;
        struct drm_display_mode *newmode;
-       u8 cea_mode;
+       u8 vic;
 
        if (video_db == NULL || video_index >= video_len)
                return NULL;
 
        /* CEA modes are numbered 1..127 */
-       cea_mode = (video_db[video_index] & 127) - 1;
-       if (cea_mode >= ARRAY_SIZE(edid_cea_modes))
+       vic = (video_db[video_index] & 127);
+       if (!drm_valid_cea_vic(vic))
                return NULL;
 
-       newmode = drm_mode_duplicate(dev, &edid_cea_modes[cea_mode]);
+       newmode = drm_mode_duplicate(dev, &edid_cea_modes[vic]);
        if (!newmode)
                return NULL;
 
@@ -2878,8 +2891,7 @@ static int add_hdmi_mode(struct drm_connector *connector, u8 vic)
        struct drm_device *dev = connector->dev;
        struct drm_display_mode *newmode;
 
-       vic--; /* VICs start at 1 */
-       if (vic >= ARRAY_SIZE(edid_4k_modes)) {
+       if (!drm_valid_hdmi_vic(vic)) {
                DRM_ERROR("Unknown HDMI VIC: %d\n", vic);
                return 0;
        }
@@ -3170,24 +3182,24 @@ static void fixup_detailed_cea_mode_clock(struct drm_display_mode *mode)
 {
        const struct drm_display_mode *cea_mode;
        int clock1, clock2, clock;
-       u8 mode_idx;
+       u8 vic;
        const char *type;
 
        /*
         * allow 5kHz clock difference either way to account for
         * the 10kHz clock resolution limit of detailed timings.
         */
-       mode_idx = drm_match_cea_mode_clock_tolerance(mode, 5) - 1;
-       if (mode_idx < ARRAY_SIZE(edid_cea_modes)) {
+       vic = drm_match_cea_mode_clock_tolerance(mode, 5);
+       if (drm_valid_cea_vic(vic)) {
                type = "CEA";
-               cea_mode = &edid_cea_modes[mode_idx];
+               cea_mode = &edid_cea_modes[vic];
                clock1 = cea_mode->clock;
                clock2 = cea_mode_alternate_clock(cea_mode);
        } else {
-               mode_idx = drm_match_hdmi_mode_clock_tolerance(mode, 5) - 1;
-               if (mode_idx < ARRAY_SIZE(edid_4k_modes)) {
+               vic = drm_match_hdmi_mode_clock_tolerance(mode, 5);
+               if (drm_valid_hdmi_vic(vic)) {
                        type = "HDMI";
-                       cea_mode = &edid_4k_modes[mode_idx];
+                       cea_mode = &edid_4k_modes[vic];
                        clock1 = cea_mode->clock;
                        clock2 = hdmi_mode_alternate_clock(cea_mode);
                } else {
@@ -3205,7 +3217,7 @@ static void fixup_detailed_cea_mode_clock(struct drm_display_mode *mode)
                return;
 
        DRM_DEBUG("detailed mode matches %s VIC %d, adjusting clock %d -> %d\n",
-                 type, mode_idx + 1, mode->clock, clock);
+                 type, vic, mode->clock, clock);
        mode->clock = clock;
 }