From 6911219ccc445f833264cf5a5a4b9439b9670b40 Mon Sep 17 00:00:00 2001 From: Julius Werner Date: Mon, 14 Mar 2016 17:29:55 -0700 Subject: edid: Add helper function to calculate bits-per-pixel dependent values Coreboot and most payloads support three basic pixel widths for the framebuffer. It assumes 32 by default, but several chipsets need to override that value with whatever else they're supporting. Our struct edid contains multiple convenience values that are directly derived from this (and other properties), so changing the bits per pixel always requires recalculating all those dependents in the chipset code. This patch provides a small convenience wrapper that can be used to consistently update the whole struct edid with a new pixel width instead, so we no longer need to duplicate those calculations everywhere. BUG=None TEST=Booted Oak in all three pixel widths (which it conveniently all supports), confirmed that images looked good. Change-Id: I5376dd4e28cf107ac2fba1dc418f5e1c5a2e2de6 Signed-off-by: Julius Werner Reviewed-on: https://review.coreboot.org/14158 Tested-by: build bot (Jenkins) Reviewed-by: Patrick Georgi --- src/lib/edid.c | 45 +++++++++++++++++++++------------------------ 1 file changed, 21 insertions(+), 24 deletions(-) (limited to 'src/lib') diff --git a/src/lib/edid.c b/src/lib/edid.c index 3aebc65e00..52898fbfa6 100644 --- a/src/lib/edid.c +++ b/src/lib/edid.c @@ -28,6 +28,7 @@ * at present. */ +#include #include #include #include @@ -478,30 +479,12 @@ detailed_block(struct edid *result_edid, unsigned char *x, int in_extension, out->mode.vso = ((x[10] >> 4) + ((x[11] & 0x0C) << 2)); out->mode.vspw = ((x[10] & 0x0F) + ((x[11] & 0x03) << 4)); out->mode.vborder = x[16]; - /* set up some reasonable defaults for payloads. - * We observe that most modern chipsets we work with - * tend to support rgb888 without regard to the - * panel bits per color or other settings. The rgb888 - * is a convenient layout for software because - * it avoids the messy bit stuffing of rgb565 or rgb444. - * It makes a reasonable trade of memory for speed. - * So, set up the default for - * 32 bits per pixel - * rgb888 (i.e. no alpha, but pixels on 32-bit boundaries) - * The mainboard can modify these if needed, though - * we have yet to see a case where that will happen. - * The existing ARM mainboards don't even call this function - * so this will not affect them. - */ - out->framebuffer_bits_per_pixel = 32; - - out->x_resolution = ALIGN(out->mode.ha * - ((out->framebuffer_bits_per_pixel + 7) / 8), - 64) / (out->framebuffer_bits_per_pixel/8); - out->y_resolution = out->mode.va; - out->bytes_per_line = ALIGN(out->mode.ha * - ((out->framebuffer_bits_per_pixel + 7)/8), - 64); + + /* We assume rgb888 (32 bits per pixel) framebuffers by default. + * Chipsets that want something else will need to override this + * with another call to edid_set_framebuffer_bits_per_pixel(). */ + edid_set_framebuffer_bits_per_pixel(out, 32); + switch ((x[17] & 0x18) >> 3) { case 0x00: extra_info.syncmethod = " analog composite"; @@ -1539,6 +1522,20 @@ int decode_edid(unsigned char *edid, int size, struct edid *out) * SPWG also says something strange about the LSB of detailed descriptor 1: * "LSB is set to "1" if panel is DE-timing only. H/V can be ignored." */ + +/* Set the framebuffer bits-per-pixel, recalculating all dependent values. */ +void edid_set_framebuffer_bits_per_pixel(struct edid *edid, int fb_bpp) +{ + /* Caller should pass a supported value, everything else is BUG(). */ + assert(fb_bpp == 32 || fb_bpp == 24 || fb_bpp == 16); + + edid->framebuffer_bits_per_pixel = fb_bpp; + edid->bytes_per_line = ALIGN_UP(edid->mode.ha * + div_round_up(fb_bpp, 8), 64); + edid->x_resolution = edid->bytes_per_line / (fb_bpp / 8); + edid->y_resolution = edid->mode.va; +} + /* * Take an edid, and create a framebuffer. Set vbe_valid to 1. */ -- cgit v1.2.3