The VESA specification suggests a 2.2 ms timeout on DDC channels.
Only the intel DRM driver implements this properly today, align all
drivers to the proper implementation.
Signed-off-by: Jean Delvare <jdelvare@xxxxxxx>
Cc: Eugeni Dodonov <eugeni@xxxxxxxxxxx>
Cc: Dave Airlie <airlied@xxxxxxxxx>
Cc: Keith Packard <keithp@xxxxxxxxxx>
Cc: Alex Deucher <alexdeucher@xxxxxxxxx>
---
drivers/gpu/drm/i915/intel_i2c.c | 2 +-
drivers/gpu/drm/nouveau/nouveau_i2c.c | 2 +-
drivers/gpu/drm/radeon/radeon_i2c.c | 4 +---
3 files changed, 3 insertions(+), 5 deletions(-)
--- linux-3.1-rc10.orig/drivers/gpu/drm/i915/intel_i2c.c 2011-10-20 14:59:11.000000000 +0200
+++ linux-3.1-rc10/drivers/gpu/drm/i915/intel_i2c.c 2011-10-20 15:24:33.000000000 +0200
@@ -183,7 +183,7 @@ intel_gpio_create(struct drm_i915_privat
gpio->algo.getsda = get_data;
gpio->algo.getscl = get_clock;
gpio->algo.udelay = I2C_RISEFALL_TIME;
- gpio->algo.timeout = usecs_to_jiffies(2200);
+ gpio->algo.timeout = usecs_to_jiffies(2200); /* from VESA */
gpio->algo.data = gpio;
if (i2c_bit_add_bus(&gpio->adapter))
--- linux-3.1-rc10.orig/drivers/gpu/drm/nouveau/nouveau_i2c.c 2011-10-20 15:14:36.000000000 +0200
+++ linux-3.1-rc10/drivers/gpu/drm/nouveau/nouveau_i2c.c 2011-10-20 15:24:37.000000000 +0200
@@ -218,7 +218,7 @@ nouveau_i2c_init(struct drm_device *dev,
if (entry->port_type < 6) {
i2c->adapter.algo_data = &i2c->bit;
i2c->bit.udelay = 10;
- i2c->bit.timeout = usecs_to_jiffies(5000);
+ i2c->bit.timeout = usecs_to_jiffies(2200); /* from VESA */
i2c->bit.data = i2c;
ret = i2c_bit_add_bus(&i2c->adapter);
} else {
--- linux-3.1-rc10.orig/drivers/gpu/drm/radeon/radeon_i2c.c 2011-10-20 14:58:17.000000000 +0200
+++ linux-3.1-rc10/drivers/gpu/drm/radeon/radeon_i2c.c 2011-10-20 15:24:41.000000000 +0200
@@ -929,9 +929,7 @@ struct radeon_i2c_chan *radeon_i2c_creat
i2c->algo.bit.getsda = get_data;
i2c->algo.bit.getscl = get_clock;
i2c->algo.bit.udelay = 10;
- /* vesa says 2.2 ms is enough, 1 jiffy doesn't seem to always
- * make this, 2 jiffies is a lot more reliable */
- i2c->algo.bit.timeout = 2;
+ i2c->algo.bit.timeout = usecs_to_jiffies(2200); /* from VESA */
i2c->algo.bit.data = i2c;
ret = i2c_bit_add_bus(&i2c->adapter);
if (ret) {
--
Jean Delvare
Suse L3
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