From 5d32b660c839706fd9a3d4b0e65cb648bc07032d Mon Sep 17 00:00:00 2001 From: Russell King Date: Sun, 1 Jul 2018 15:46:54 +0100 Subject: [PATCH] drm/armada: add comments about HWC32 cursor colour format Add some comments about the format of the HWC32 cursor colour format. Signed-off-by: Russell King --- drivers/gpu/drm/armada/armada_crtc.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/gpu/drm/armada/armada_crtc.c b/drivers/gpu/drm/armada/armada_crtc.c index 5991feb1bcc9..e81e57823b66 100644 --- a/drivers/gpu/drm/armada/armada_crtc.c +++ b/drivers/gpu/drm/armada/armada_crtc.c @@ -515,6 +515,13 @@ static void armada_load_cursor_argb(void __iomem *base, uint32_t *pix, for (x = 0; x < width; x++, p++) { uint32_t val = *p; + /* + * In "ARGB888" (HWC32) mode, writing to the SRAM + * requires these bits to contain: + * 31:24 = alpha 23:16 = blue 15:8 = green 7:0 = red + * So, it's actually ABGR8888. This is independent + * of the SWAPRB bits in DMA control register 0. + */ val = (val & 0xff00ff00) | (val & 0x000000ff) << 16 | (val & 0x00ff0000) >> 16; -- 2.30.2