This allows to avoid talking to a non-responding bus repeatedly until we finally timeout after 15 attempts. We can do this by catching the -ENXIO error, provided by i2c_algo_bit:bit_doAddress call. Within the bit_doAddress we already try 3 times to get the edid data, so if the routine tells us that bus is not responding, it is mostly pointless to keep re-trying those attempts over and over again until we reach final number of retries. This change should fix https://bugs.freedesktop.org/show_bug.cgi?id=41059 and improve overall edid detection timing by 10-30% in most cases, and by a much larger margin in case of phantom outputs. Timing results for i915-powered machines for 'time xrandr' command: Machine 1: from 0.840s to 0.290s Machine 2: from 0.315s to 0.280s Machine 3: from +/- 1s to 0.184s Timing results for HD5770 with 'time xrandr' command: Machine 4: from 3.210s to 1.060s v2: added a module parameter to control this behavior. The idea came from discussion with Jean Delvare. v3: added external tested-by's and timing results. Signed-off-by: Eugeni Dodonov <eugeni.dodonov@xxxxxxxxx> Tested-By: Sean Finney <seanius@xxxxxxxxxxx> Tested-By: Soren Hansen <soren@xxxxxxxxxxx> Tested-By: Hernando Torque <sirius@xxxxxxxxxxxxxxxx> --- drivers/gpu/drm/drm_edid.c | 5 +++++ drivers/gpu/drm/drm_stub.c | 5 +++++ include/drm/drmP.h | 2 ++ 3 files changed, 12 insertions(+), 0 deletions(-) diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 7425e5c..c7426ab 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -265,6 +265,11 @@ drm_do_probe_ddc_edid(struct i2c_adapter *adapter, unsigned char *buf, } }; ret = i2c_transfer(adapter, msgs, 2); + if (drm_ignore_unresponsive_edid && ret == -ENXIO) { + DRM_DEBUG_KMS("drm: skipping non-existent adapter %s\n", + adapter->name); + break; + } } while (ret != 2 && --retries); return ret == 2 ? 0 : -1; diff --git a/drivers/gpu/drm/drm_stub.c b/drivers/gpu/drm/drm_stub.c index 6d7b083..b1013fe 100644 --- a/drivers/gpu/drm/drm_stub.c +++ b/drivers/gpu/drm/drm_stub.c @@ -46,16 +46,21 @@ EXPORT_SYMBOL(drm_vblank_offdelay); unsigned int drm_timestamp_precision = 20; /* Default to 20 usecs. */ EXPORT_SYMBOL(drm_timestamp_precision); +unsigned int drm_ignore_unresponsive_edid = 1; /* Ignore non-responding edid by default */ +EXPORT_SYMBOL(drm_ignore_unresponsive_edid); + MODULE_AUTHOR(CORE_AUTHOR); MODULE_DESCRIPTION(CORE_DESC); MODULE_LICENSE("GPL and additional rights"); MODULE_PARM_DESC(debug, "Enable debug output"); MODULE_PARM_DESC(vblankoffdelay, "Delay until vblank irq auto-disable [msecs]"); MODULE_PARM_DESC(timestamp_precision_usec, "Max. error on timestamps [usecs]"); +MODULE_PARM_DESC(ignore_unresponsive_edid, "Automatically ignore outputs which do not provide EDID after 3 attempts"); module_param_named(debug, drm_debug, int, 0600); module_param_named(vblankoffdelay, drm_vblank_offdelay, int, 0600); module_param_named(timestamp_precision_usec, drm_timestamp_precision, int, 0600); +module_param_named(ignore_unresponsive_edid, drm_ignore_unresponsive_edid, int, 0600); struct idr drm_minors_idr; diff --git a/include/drm/drmP.h b/include/drm/drmP.h index 9b7c2bb..d7b0286 100644 --- a/include/drm/drmP.h +++ b/include/drm/drmP.h @@ -1465,6 +1465,8 @@ extern unsigned int drm_debug; extern unsigned int drm_vblank_offdelay; extern unsigned int drm_timestamp_precision; +extern unsigned int drm_ignore_unresponsive_edid; + extern struct class *drm_class; extern struct proc_dir_entry *drm_proc_root; extern struct dentry *drm_debugfs_root; -- 1.7.7.1 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
