Re: [PATCH v2 3/7] drm_modes: add videomode_from_drm_display_mode

On 19/12/14 11:03, Philipp Zabel wrote:

Am Donnerstag, den 18.12.2014, 18:00 -0800 schrieb Steve Longerbeam:

quoted

Add conversion from drm_display_mode to videomode.

Signed-off-by: Steve Longerbeam <redacted>
---
 drivers/gpu/drm/drm_modes.c |   40 ++++++++++++++++++++++++++++++++++++++++
 include/drm/drm_modes.h     |    2 ++
 2 files changed, 42 insertions(+)

diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
index 6d8b941..583a391 100644
--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c

@@ -615,6 +615,46 @@ void drm_display_mode_from_videomode(const struct videomode *vm,
 }
 EXPORT_SYMBOL_GPL(drm_display_mode_from_videomode);
 
+/**
+ * videomode_from_drm_display_mode - fill in @vm using @dmode,
+ * @dmode: drm_display_mode structure to use as source
+ * @vm: videomode structure to use as destination
+ *
+ * Fills out @vm using the display mode specified in @dmode.
+ */
+void videomode_from_drm_display_mode(const struct drm_display_mode *dmode,
+				     struct videomode *vm)
+{
+	vm->hactive = dmode->hdisplay;
+	vm->hfront_porch = dmode->hsync_start - dmode->hdisplay;
+	vm->hsync_len = dmode->hsync_end - dmode->hsync_start;
+	vm->hback_porch = dmode->htotal - dmode->hsync_end;
+
+	vm->vactive = dmode->vdisplay;
+	vm->vfront_porch = dmode->vsync_start - dmode->vdisplay;
+	vm->vsync_len = dmode->vsync_end - dmode->vsync_start;
+	vm->vback_porch = dmode->vtotal - dmode->vsync_end;
+
+	vm->pixelclock = dmode->clock * 1000;
+
+	vm->flags = 0;
+	if (dmode->flags & DRM_MODE_FLAG_PHSYNC)
+		vm->flags |= DISPLAY_FLAGS_HSYNC_HIGH;
+	else if (dmode->flags & DRM_MODE_FLAG_NHSYNC)
+		vm->flags |= DISPLAY_FLAGS_HSYNC_LOW;
+	if (dmode->flags & DRM_MODE_FLAG_PVSYNC)
+		vm->flags |= DISPLAY_FLAGS_VSYNC_HIGH;
+	else if (dmode->flags & DRM_MODE_FLAG_NVSYNC)
+		vm->flags |= DISPLAY_FLAGS_VSYNC_LOW;
+	if (dmode->flags & DRM_MODE_FLAG_INTERLACE)
+		vm->flags |= DISPLAY_FLAGS_INTERLACED;
+	if (dmode->flags & DRM_MODE_FLAG_DBLSCAN)
+		vm->flags |= DISPLAY_FLAGS_DOUBLESCAN;
+	if (dmode->flags & DRM_MODE_FLAG_DBLCLK)
+		vm->flags |= DISPLAY_FLAGS_DOUBLECLK;
+}
+EXPORT_SYMBOL_GPL(videomode_from_drm_display_mode);

Is it ok for drm_modes to export a function that doesn't start with
drm_ ? We could just rename this to drm_display_mode_to_videomode if
necessary. I can fix it up as I apply it, but I'd like to know which is
preferred.

Non-native English speaker here, and drm_display_mode_to_videomode
sounds better. Plus I think that *to* functions are more common than
*from* ones.

I'm not a drm dev, so just my 2c :)

Cheers,
Emil