On Wed, 08 Apr 2015, "R, Durgadoss" <durgadoss.r@xxxxxxxxx> wrote: >>-----Original Message----- >>From: Nikula, Jani >>Sent: Wednesday, April 8, 2015 1:34 PM >>To: R, Durgadoss; intel-gfx@xxxxxxxxxxxxxxxxxxxxx >>Cc: R, Durgadoss >>Subject: Re: [PATCH] drm/i915: Add debugfs to read any DPCD register >> >>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? > > Ok.. Will remove this check in next version.. Maybe we should check for some of the intermediate steps in figuring out intel_dp instead. I know, my dpcd dump doesn't do that either... :( BR, Jani. > >> >>> + >>> + 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. > > I added this because we don't have locking constructs for > our state. > > For tools, yes, I agree that just a value would do.. > > Thanks, > Durga > >> >>> + 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 -- Jani Nikula, Intel Open Source Technology Center _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
