From 5a4e88cf3b64c4a5c92e43a90260c34a6a52d011 Mon Sep 17 00:00:00 2001 From: Konstantin Nazarov Date: Tue, 27 Apr 2021 17:08:23 +0200 Subject: [PATCH] edid: allow arbitrary-length checksums Some of the EDID extensions like DisplayID do checksums of their subsections. Currently checksums can be only applied to the whole extension blocks which are 128 bytes. This patch allows to checksum arbitrary parts of EDID, and not only whole extension blocks. Based-on: <20210303152948.59943-2-akihiko.odaki@gmail.com> Signed-off-by: Konstantin Nazarov Message-Id: <20210315114639.91953-2-mail@knazarov.com> Signed-off-by: Gerd Hoffmann Message-id: 20210427150824.638359-1-kraxel@redhat.com Message-Id: <20210427150824.638359-8-kraxel@redhat.com> --- hw/display/edid-generate.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/hw/display/edid-generate.c b/hw/display/edid-generate.c index b70ab1557e..bdd01571fc 100644 --- a/hw/display/edid-generate.c +++ b/hw/display/edid-generate.c @@ -159,17 +159,17 @@ static void edid_fill_modes(uint8_t *edid, uint8_t *xtra3, uint8_t *dta, } } -static void edid_checksum(uint8_t *edid) +static void edid_checksum(uint8_t *edid, size_t len) { uint32_t sum = 0; int i; - for (i = 0; i < 127; i++) { + for (i = 0; i < len; i++) { sum += edid[i]; } sum &= 0xff; if (sum) { - edid[127] = 0x100 - sum; + edid[len] = 0x100 - sum; } } @@ -474,9 +474,9 @@ void qemu_edid_generate(uint8_t *edid, size_t size, /* =============== finish up =============== */ - edid_checksum(edid); + edid_checksum(edid, 127); if (dta) { - edid_checksum(dta); + edid_checksum(dta, 127); } }