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In rev 1.0a of the Intel High Definition Audio Spec:

Browse Source 
https://www.intel.com/content/www/us/en/standards/
		high-definition-audio-specification.html

page 186 shows the layout of the baseline block of the ELD (EDID Like Data)
struct - and allows a reserved (effectively padding) area at the end of the
struct.  This is required to keep the struct an even number of words long
(size measured in units of 32 bits) while allowing for a variable length
monitor name, followed by a variable number of 3 byte structs - the
combination of which is not likely to be a multiple of 4.

Code here assumed that there was no padding, and objected to the ELD
format if any padding bytes existed (hdafg_dd_parse_info() would return
EINVAL) causing a "failed to parse ELD data" message (if HDAFG_HDMI_DEBUG
is defined) from hdafg_assoc_dump_dd() making it difficult (or at least
confusing) to debug HDMI related audio issues (hdafg_assoc_dump_dd would
not print most of the data it is expected to print) although this would
most likely have no effect on actual operations.

Change a test from a != to < (there must be enough data, not exactly the
amount needed) for the EINVAL.   As a consequence, the length after the
SAD data is parsed (the 3 byte structs) is no longer required to be 0,
so remove the KASSERT() (previously it was just useless, the code guaranteed
a 0 value, now it is incorrect.)   While here also change a related
diagnostic message to be slightly more informative as to what is being shown.

OK jmcneill@
This commit is contained in:
kre 2017-09-26 09:24:22 +00:00
parent 82fd8c9b22
commit 659488a459
1 changed files with 4 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
sys/dev/hdaudio/hdafg_dd.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: hdafg_dd.c,v 1.2 2017/08/04 00:25:23 mrg Exp $ */
/* $NetBSD: hdafg_dd.c,v 1.3 2017/09/26 09:24:22 kre Exp $ */
/*
* Copyright (c) 2011 Jared D. McNeill <jmcneill@invisible.ca>
@ -30,7 +30,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: hdafg_dd.c,v 1.2 2017/08/04 00:25:23 mrg Exp $");
__KERNEL_RCSID(0, "$NetBSD: hdafg_dd.c,v 1.3 2017/09/26 09:24:22 kre Exp $");
#include <sys/types.h>
#include <sys/param.h>
@ -92,7 +92,7 @@ hdafg_dd_parse_info(uint8_t *data, size_t datalen, struct hdafg_dd_info *hdi)
data += ELD_MNL(block);
datalen -= ELD_MNL(block);
if (datalen != ELD_SAD_COUNT(block) * sizeof(hdi->sad[0])) {
if (datalen < ELD_SAD_COUNT(block) * sizeof(hdi->sad[0])) {
#ifdef HDAFG_HDMI_DEBUG
printf(" datalen %u sadcount %u sizeof sad %u\n",
(unsigned int)datalen,
@ -109,10 +109,8 @@ hdafg_dd_parse_info(uint8_t *data, size_t datalen, struct hdafg_dd_info *hdi)
}
#ifdef HDAFG_HDMI_DEBUG
printf("datalen = %u\n", (unsigned int)datalen);
printf("hdafg eld padding ignored = %u\n", (unsigned int)datalen);
#endif
KASSERT(datalen == 0);
return 0;
}