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authorWu Fengguang <fengguang.wu@intel.com>2011-11-22 16:46:23 +0800
committerTakashi Iwai <tiwai@suse.de>2011-11-22 12:09:45 +0100
commita370fc62b9ad3f73abe2a721de6c03cdcce95b54 (patch)
tree8354755e29727b65ab8fbf89a428462780c47d1d /sound
parenta29878553a9a7b4c06f93c7e383527cf014d4ceb (diff)
downloadlinux-stericsson-a370fc62b9ad3f73abe2a721de6c03cdcce95b54.tar.gz
ALSA: hda - fail ELD reading early
With the ELD repoll mechanism, we can (and should) fail the ELD reading immediately when find something obviously wrong and let the caller retry after some delay. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound')
-rw-r--r--sound/pci/hda/hda_eld.c28
1 files changed, 19 insertions, 9 deletions
diff --git a/sound/pci/hda/hda_eld.c b/sound/pci/hda/hda_eld.c
index 7ae7578bdcc0..c1da422e085a 100644
--- a/sound/pci/hda/hda_eld.c
+++ b/sound/pci/hda/hda_eld.c
@@ -347,18 +347,28 @@ int snd_hdmi_get_eld(struct hdmi_eld *eld,
for (i = 0; i < size; i++) {
unsigned int val = hdmi_get_eld_data(codec, nid, i);
+ /*
+ * Graphics driver might be writing to ELD buffer right now.
+ * Just abort. The caller will repoll after a while.
+ */
if (!(val & AC_ELDD_ELD_VALID)) {
- if (!i) {
- snd_printd(KERN_INFO
- "HDMI: invalid ELD data\n");
- ret = -EINVAL;
- goto error;
- }
snd_printd(KERN_INFO
"HDMI: invalid ELD data byte %d\n", i);
- val = 0;
- } else
- val &= AC_ELDD_ELD_DATA;
+ ret = -EINVAL;
+ goto error;
+ }
+ val &= AC_ELDD_ELD_DATA;
+ /*
+ * The first byte cannot be zero. This can happen on some DVI
+ * connections. Some Intel chips may also need some 250ms delay
+ * to return non-zero ELD data, even when the graphics driver
+ * correctly writes ELD content before setting ELD_valid bit.
+ */
+ if (!val && !i) {
+ snd_printdd(KERN_INFO "HDMI: 0 ELD data\n");
+ ret = -EINVAL;
+ goto error;
+ }
buf[i] = val;
}