On Wed, 08 Apr 2015, Durgadoss R <durgadoss.r@xxxxxxxxx> wrote: > This patch creates a connector specific debugfs > interface to read any particular DPCD register. > The DPCD register address (hex format) is written > to 'i915_dpcd_addr' interface and the corresponding > value can be read from 'i915_dpcd_val' interface. > > Example usage: > echo 0x70 > i915_dpcd_addr > cat i915_dpcd_val > DPCD[0x70]:0x1 I am still not overjoyed about the interface (because it has a state), but I don't have anything better to suggest either. I'll defer to others to make the taste judgement... Review comments for the implementation inline. BR, Jani. > > Signed-off-by: Durgadoss R <durgadoss.r@xxxxxxxxx> > --- > This patch is based on top of Jani's patch: > "add i915 specific connector debugfs file for DPCD" > [https://freedesktop.org/patch/43332/] Already committed. > > drivers/gpu/drm/i915/i915_debugfs.c | 102 +++++++++++++++++++++++++++++++++++- > drivers/gpu/drm/i915/intel_drv.h | 1 + > 2 files changed, 102 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c > index 10ca511..9951d84 100644 > --- a/drivers/gpu/drm/i915/i915_debugfs.c > +++ b/drivers/gpu/drm/i915/i915_debugfs.c > @@ -4865,6 +4865,101 @@ static const struct file_operations i915_dpcd_fops = { > .release = single_release, > }; > > +static ssize_t i915_dpcd_addr_write(struct file *file, const char __user *ubuf, > + size_t len, loff_t *offp) > +{ > + struct seq_file *m = file->private_data; > + struct drm_connector *connector = m->private; > + struct intel_dp *intel_dp = > + enc_to_intel_dp(&intel_attached_encoder(connector)->base); > + unsigned int reg_addr; > + char tmp[16]; > + int ret; > + > + if (!intel_dp) > + return -EINVAL; I think it's highly unlikely this will be NULL. You're more likely to oops above if something went wrong (see enc_to_intel_dp and intel_attached_encoder). Also, -ENODEV? > + > + if (len >= sizeof(tmp)) > + return -EINVAL; > + > + if (copy_from_user(tmp, ubuf, len)) > + return -EFAULT; > + > + tmp[len] = '\0'; > + > + ret = sscanf(tmp, "%x\n", ®_addr); See kstrtouint. > + if (ret == 0) > + return -EINVAL; > + > + intel_dp->debugfs_dpcd_addr = reg_addr; > + > + return len; > +} > + > +static int i915_dpcd_addr_show(struct seq_file *m, void *data) > +{ > + struct drm_connector *connector = m->private; > + struct intel_dp *intel_dp = > + enc_to_intel_dp(&intel_attached_encoder(connector)->base); > + > + if (!intel_dp) > + return -EINVAL; Same as above. > + > + seq_printf(m, "0x%x\n", intel_dp->debugfs_dpcd_addr); > + > + return 0; > +} > + > +static int i915_dpcd_addr_open(struct inode *inode, struct file *file) > +{ > + return single_open(file, i915_dpcd_addr_show, inode->i_private); > +} > + > +static const struct file_operations i915_dpcd_addr_fops = { > + .owner = THIS_MODULE, > + .open = i915_dpcd_addr_open, > + .read = seq_read, > + .write = i915_dpcd_addr_write, > + .llseek = seq_lseek, > + .release = single_release, > +}; > + > +static int i915_dpcd_val_show(struct seq_file *m, void *data) > +{ > + struct drm_connector *connector = m->private; > + struct intel_dp *intel_dp = > + enc_to_intel_dp(&intel_attached_encoder(connector)->base); > + unsigned int addr; > + u8 buf[1]; Might be more obvious to just have u8 val, and use a pointer to it. *shrug*. > + int ret; > + > + if (!intel_dp) > + return -EINVAL; Same as above. > + > + addr = intel_dp->debugfs_dpcd_addr; > + ret = drm_dp_dpcd_readb(&intel_dp->aux, addr, buf); > + if (ret < 0) { > + DRM_ERROR("dpcd read for 0x%x failed:%d\n", addr, ret); I think there'll already be errors in the log at this point. This is probably redundant. > + return ret; > + } > + > + seq_printf(m, "DPCD[0x%x]:0x%x\n", addr, buf[0]); For an interface better suited for tools than humans, I'd drop all the fluff and just print the content. Maybe use 0x%02x for format. > + return 0; > +} > + > +static int i915_dpcd_val_open(struct inode *inode, struct file *file) > +{ > + return single_open(file, i915_dpcd_val_show, inode->i_private); > +} > + > +static const struct file_operations i915_dpcd_val_fops = { > + .owner = THIS_MODULE, > + .open = i915_dpcd_val_open, > + .read = seq_read, > + .llseek = seq_lseek, > + .release = single_release, > +}; > + > /** > * i915_debugfs_connector_add - add i915 specific connector debugfs files > * @connector: pointer to a registered drm_connector > @@ -4883,9 +4978,14 @@ int i915_debugfs_connector_add(struct drm_connector *connector) > return -ENODEV; > > if (connector->connector_type == DRM_MODE_CONNECTOR_DisplayPort || > - connector->connector_type == DRM_MODE_CONNECTOR_eDP) > + connector->connector_type == DRM_MODE_CONNECTOR_eDP) { > debugfs_create_file("i915_dpcd", S_IRUGO, root, connector, > &i915_dpcd_fops); > + debugfs_create_file("i915_dpcd_addr", S_IRUGO | S_IWUSR, > + root, connector, &i915_dpcd_addr_fops); > + debugfs_create_file("i915_dpcd_val", S_IRUGO, root, > + connector, &i915_dpcd_val_fops); > + } > > return 0; > } > diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h > index 4799b11..0594baa 100644 > --- a/drivers/gpu/drm/i915/intel_drv.h > +++ b/drivers/gpu/drm/i915/intel_drv.h > @@ -642,6 +642,7 @@ struct intel_dp { > unsigned long last_power_cycle; > unsigned long last_power_on; > unsigned long last_backlight_off; > + unsigned int debugfs_dpcd_addr; > > struct notifier_block edp_notifier; > > -- > 1.9.1 > -- Jani Nikula, Intel Open Source Technology Center _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
