[alsa-devel] [PATCH v2 3/4] ALSA: hda - hdmi: protect access to ELD buffer
David Henningsson
david.henningsson at canonical.com
Tue Feb 19 09:47:36 CET 2013
Because the eld buffer can be simultaneously accessed from both
workqueue context (updating) and process context (kcontrol read),
we need to protect it with a spinlock to guarantee consistency.
To avoid holding the spinlock while reading the ELD info from the
codec, we introduce a temporary eld buffer.
Signed-off-by: David Henningsson <david.henningsson at canonical.com>
---
sound/pci/hda/hda_eld.c | 12 +++++++++---
sound/pci/hda/hda_local.h | 3 +++
sound/pci/hda/patch_hdmi.c | 32 +++++++++++++++++++++++++-------
3 files changed, 37 insertions(+), 10 deletions(-)
diff --git a/sound/pci/hda/hda_eld.c b/sound/pci/hda/hda_eld.c
index 4c054f4..766f011 100644
--- a/sound/pci/hda/hda_eld.c
+++ b/sound/pci/hda/hda_eld.c
@@ -490,7 +490,7 @@ static void hdmi_print_eld_info(struct snd_info_entry *entry,
struct hdmi_eld *e = entry->private_data;
char buf[SND_PRINT_CHANNEL_ALLOCATION_ADVISED_BUFSIZE];
int i;
- static char *eld_versoin_names[32] = {
+ static char *eld_version_names[32] = {
"reserved",
"reserved",
"CEA-861D or below",
@@ -505,15 +505,18 @@ static void hdmi_print_eld_info(struct snd_info_entry *entry,
[4 ... 7] = "reserved"
};
+ spin_lock(&e->lock);
snd_iprintf(buffer, "monitor_present\t\t%d\n", e->monitor_present);
snd_iprintf(buffer, "eld_valid\t\t%d\n", e->eld_valid);
- if (!e->eld_valid)
+ if (!e->eld_valid) {
+ spin_unlock(&e->lock);
return;
+ }
snd_iprintf(buffer, "monitor_name\t\t%s\n", e->monitor_name);
snd_iprintf(buffer, "connection_type\t\t%s\n",
eld_connection_type_names[e->conn_type]);
snd_iprintf(buffer, "eld_version\t\t[0x%x] %s\n", e->eld_ver,
- eld_versoin_names[e->eld_ver]);
+ eld_version_names[e->eld_ver]);
snd_iprintf(buffer, "edid_version\t\t[0x%x] %s\n", e->cea_edid_ver,
cea_edid_version_names[e->cea_edid_ver]);
snd_iprintf(buffer, "manufacture_id\t\t0x%x\n", e->manufacture_id);
@@ -530,6 +533,7 @@ static void hdmi_print_eld_info(struct snd_info_entry *entry,
for (i = 0; i < e->sad_count; i++)
hdmi_print_sad_info(i, e->sad + i, buffer);
+ spin_unlock(&e->lock);
}
static void hdmi_write_eld_info(struct snd_info_entry *entry,
@@ -542,6 +546,7 @@ static void hdmi_write_eld_info(struct snd_info_entry *entry,
long long val;
unsigned int n;
+ spin_lock(&e->lock);
while (!snd_info_get_line(buffer, line, sizeof(line))) {
if (sscanf(line, "%s %llx", name, &val) != 2)
continue;
@@ -593,6 +598,7 @@ static void hdmi_write_eld_info(struct snd_info_entry *entry,
e->sad_count = n + 1;
}
}
+ spin_unlock(&e->lock);
}
diff --git a/sound/pci/hda/hda_local.h b/sound/pci/hda/hda_local.h
index 05f1d59..b2d6a9e 100644
--- a/sound/pci/hda/hda_local.h
+++ b/sound/pci/hda/hda_local.h
@@ -712,8 +712,11 @@ struct cea_sad {
/*
* ELD: EDID Like Data
+ *
+ * Note: The order of these fields is used in hdmi_present_sense
*/
struct hdmi_eld {
+ spinlock_t lock;
bool monitor_present;
bool eld_valid;
int eld_size;
diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c
index 7a73dfb..52b1afc 100644
--- a/sound/pci/hda/patch_hdmi.c
+++ b/sound/pci/hda/patch_hdmi.c
@@ -91,6 +91,7 @@ struct hdmi_spec {
struct hda_pcm pcm_rec[MAX_HDMI_PINS];
unsigned int channels_max; /* max over all cvts */
+ struct hdmi_eld temp_eld;
/*
* Non-generic ATI/NVIDIA specific
*/
@@ -352,7 +353,9 @@ static int hdmi_eld_ctl_info(struct snd_kcontrol *kcontrol,
pin_idx = kcontrol->private_value;
eld = &spec->pins[pin_idx].sink_eld;
+ spin_lock(&eld->lock);
uinfo->count = eld->eld_valid ? eld->eld_size : 0;
+ spin_unlock(&eld->lock);
return 0;
}
@@ -368,7 +371,9 @@ static int hdmi_eld_ctl_get(struct snd_kcontrol *kcontrol,
pin_idx = kcontrol->private_value;
eld = &spec->pins[pin_idx].sink_eld;
+ spin_lock(&eld->lock);
if (eld->eld_size > ARRAY_SIZE(ucontrol->value.bytes.data)) {
+ spin_unlock(&eld->lock);
snd_BUG();
return -EINVAL;
}
@@ -376,6 +381,7 @@ static int hdmi_eld_ctl_get(struct snd_kcontrol *kcontrol,
if (eld->eld_valid)
memcpy(ucontrol->value.bytes.data, eld->eld_buffer,
eld->eld_size);
+ spin_unlock(&eld->lock);
return 0;
}
@@ -1162,7 +1168,9 @@ static int hdmi_read_pin_conn(struct hda_codec *codec, int pin_idx)
static void hdmi_present_sense(struct hdmi_spec_per_pin *per_pin, int repoll)
{
struct hda_codec *codec = per_pin->codec;
- struct hdmi_eld *eld = &per_pin->sink_eld;
+ struct hdmi_spec *spec = codec->spec;
+ struct hdmi_eld *eld = &spec->temp_eld;
+ struct hdmi_eld *pin_eld = &per_pin->sink_eld;
hda_nid_t pin_nid = per_pin->pin_nid;
/*
* Always execute a GetPinSense verb here, even when called from
@@ -1173,28 +1181,37 @@ static void hdmi_present_sense(struct hdmi_spec_per_pin *per_pin, int repoll)
* the unsolicited response to avoid custom WARs.
*/
int present = snd_hda_pin_sense(codec, pin_nid);
- bool eld_valid = false;
+ bool update_eld = false;
memset(eld, 0, offsetof(struct hdmi_eld, eld_buffer));
eld->monitor_present = !!(present & AC_PINSENSE_PRESENCE);
if (eld->monitor_present)
- eld_valid = !!(present & AC_PINSENSE_ELDV);
+ eld->eld_valid = !!(present & AC_PINSENSE_ELDV);
_snd_printd(SND_PR_VERBOSE,
"HDMI status: Codec=%d Pin=%d Presence_Detect=%d ELD_Valid=%d\n",
- codec->addr, pin_nid, eld->monitor_present, eld_valid);
+ codec->addr, pin_nid, eld->monitor_present, eld->eld_valid);
- eld->eld_valid = false;
- if (eld_valid) {
- if (!snd_hdmi_get_eld(eld, codec, pin_nid))
+ if (eld->eld_valid) {
+ if (!snd_hdmi_get_eld(eld, codec, pin_nid)) {
snd_hdmi_show_eld(eld);
+ update_eld = true;
+ }
else if (repoll) {
queue_delayed_work(codec->bus->workq,
&per_pin->work,
msecs_to_jiffies(300));
}
}
+
+ spin_lock(&pin_eld->lock);
+ if (pin_eld->eld_valid && !eld->eld_valid)
+ update_eld = true;
+ if (update_eld)
+ memcpy(&pin_eld->monitor_present, &eld->monitor_present,
+ sizeof(struct hdmi_eld) - sizeof(spinlock_t));
+ spin_unlock(&pin_eld->lock);
}
static void hdmi_repoll_eld(struct work_struct *work)
@@ -1662,6 +1679,7 @@ static int generic_hdmi_init_per_pins(struct hda_codec *codec)
struct hdmi_eld *eld = &per_pin->sink_eld;
per_pin->codec = codec;
+ spin_lock_init(&eld->lock);
INIT_DELAYED_WORK(&per_pin->work, hdmi_repoll_eld);
snd_hda_eld_proc_new(codec, eld, pin_idx);
}
--
1.7.9.5
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