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5eff9585de
Inside drm_clients_info, the rcu_read_lock is held to lock pid_task()->comm. However, within this protected section, a call to drm_is_current_master is made, which involves a mutex lock in a future patch. However, this is illegal because the mutex lock might block while in the RCU read-side critical section. Since drm_is_current_master isn't protected by rcu_read_lock, we avoid this by moving it out of the RCU critical section. The following report came from intel-gfx ci's igt@debugfs_test@read_all_entries testcase: ============================= [ BUG: Invalid wait context ] 5.13.0-CI-Patchwork_20515+ #1 Tainted: G W ----------------------------- debugfs_test/1101 is trying to lock: ffff888132d901a8 (&dev->master_mutex){+.+.}-{3:3}, at: drm_is_current_master+0x1e/0x50 other info that might help us debug this: context-{4:4} 3 locks held by debugfs_test/1101: #0: ffff88810fdffc90 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0x53/0x3b0 #1: ffff888132d90240 (&dev->filelist_mutex){+.+.}-{3:3}, at: drm_clients_info+0x63/0x2a0 #2: ffffffff82734220 (rcu_read_lock){....}-{1:2}, at: drm_clients_info+0x1b1/0x2a0 stack backtrace: CPU: 8 PID: 1101 Comm: debugfs_test Tainted: G W 5.13.0-CI-Patchwork_20515+ #1 Hardware name: Intel Corporation CometLake Client Platform/CometLake S UDIMM (ERB/CRB), BIOS CMLSFWR1.R00.1263.D00.1906260926 06/26/2019 Call Trace: dump_stack+0x7f/0xad __lock_acquire.cold.78+0x2af/0x2ca lock_acquire+0xd3/0x300 ? drm_is_current_master+0x1e/0x50 ? __mutex_lock+0x76/0x970 ? lockdep_hardirqs_on+0xbf/0x130 __mutex_lock+0xab/0x970 ? drm_is_current_master+0x1e/0x50 ? drm_is_current_master+0x1e/0x50 ? drm_is_current_master+0x1e/0x50 drm_is_current_master+0x1e/0x50 drm_clients_info+0x107/0x2a0 seq_read_iter+0x178/0x3b0 seq_read+0x104/0x150 full_proxy_read+0x4e/0x80 vfs_read+0xa5/0x1b0 ksys_read+0x5a/0xd0 do_syscall_64+0x39/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xae Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20210712043508.11584-3-desmondcheongzx@gmail.com
476 lines
12 KiB
C
476 lines
12 KiB
C
/*
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* Created: Sun Dec 21 13:08:50 2008 by bgamari@gmail.com
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*
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* Copyright 2008 Ben Gamari <bgamari@gmail.com>
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
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* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
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* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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* OTHER DEALINGS IN THE SOFTWARE.
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*/
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#include <linux/debugfs.h>
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#include <linux/export.h>
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#include <linux/seq_file.h>
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#include <linux/slab.h>
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#include <linux/uaccess.h>
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#include <drm/drm_atomic.h>
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#include <drm/drm_auth.h>
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#include <drm/drm_client.h>
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#include <drm/drm_debugfs.h>
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#include <drm/drm_device.h>
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#include <drm/drm_drv.h>
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#include <drm/drm_edid.h>
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#include <drm/drm_file.h>
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#include <drm/drm_gem.h>
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#include "drm_crtc_internal.h"
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#include "drm_internal.h"
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#if defined(CONFIG_DEBUG_FS)
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/***************************************************
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* Initialization, etc.
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**************************************************/
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static int drm_name_info(struct seq_file *m, void *data)
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{
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struct drm_info_node *node = (struct drm_info_node *) m->private;
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struct drm_minor *minor = node->minor;
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struct drm_device *dev = minor->dev;
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struct drm_master *master;
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mutex_lock(&dev->master_mutex);
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master = dev->master;
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seq_printf(m, "%s", dev->driver->name);
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if (dev->dev)
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seq_printf(m, " dev=%s", dev_name(dev->dev));
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if (master && master->unique)
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seq_printf(m, " master=%s", master->unique);
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if (dev->unique)
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seq_printf(m, " unique=%s", dev->unique);
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seq_printf(m, "\n");
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mutex_unlock(&dev->master_mutex);
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return 0;
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}
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static int drm_clients_info(struct seq_file *m, void *data)
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{
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struct drm_info_node *node = (struct drm_info_node *) m->private;
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struct drm_device *dev = node->minor->dev;
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struct drm_file *priv;
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kuid_t uid;
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seq_printf(m,
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"%20s %5s %3s master a %5s %10s\n",
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"command",
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"pid",
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"dev",
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"uid",
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"magic");
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/* dev->filelist is sorted youngest first, but we want to present
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* oldest first (i.e. kernel, servers, clients), so walk backwardss.
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*/
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mutex_lock(&dev->filelist_mutex);
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list_for_each_entry_reverse(priv, &dev->filelist, lhead) {
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struct task_struct *task;
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bool is_current_master = drm_is_current_master(priv);
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rcu_read_lock(); /* locks pid_task()->comm */
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task = pid_task(priv->pid, PIDTYPE_PID);
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uid = task ? __task_cred(task)->euid : GLOBAL_ROOT_UID;
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seq_printf(m, "%20s %5d %3d %c %c %5d %10u\n",
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task ? task->comm : "<unknown>",
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pid_vnr(priv->pid),
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priv->minor->index,
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is_current_master ? 'y' : 'n',
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priv->authenticated ? 'y' : 'n',
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from_kuid_munged(seq_user_ns(m), uid),
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priv->magic);
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rcu_read_unlock();
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}
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mutex_unlock(&dev->filelist_mutex);
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return 0;
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}
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static int drm_gem_one_name_info(int id, void *ptr, void *data)
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{
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struct drm_gem_object *obj = ptr;
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struct seq_file *m = data;
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seq_printf(m, "%6d %8zd %7d %8d\n",
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obj->name, obj->size,
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obj->handle_count,
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kref_read(&obj->refcount));
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return 0;
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}
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static int drm_gem_name_info(struct seq_file *m, void *data)
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{
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struct drm_info_node *node = (struct drm_info_node *) m->private;
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struct drm_device *dev = node->minor->dev;
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seq_printf(m, " name size handles refcount\n");
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mutex_lock(&dev->object_name_lock);
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idr_for_each(&dev->object_name_idr, drm_gem_one_name_info, m);
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mutex_unlock(&dev->object_name_lock);
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return 0;
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}
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static const struct drm_info_list drm_debugfs_list[] = {
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{"name", drm_name_info, 0},
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{"clients", drm_clients_info, 0},
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{"gem_names", drm_gem_name_info, DRIVER_GEM},
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};
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#define DRM_DEBUGFS_ENTRIES ARRAY_SIZE(drm_debugfs_list)
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static int drm_debugfs_open(struct inode *inode, struct file *file)
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{
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struct drm_info_node *node = inode->i_private;
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return single_open(file, node->info_ent->show, node);
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}
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static const struct file_operations drm_debugfs_fops = {
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.owner = THIS_MODULE,
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.open = drm_debugfs_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release,
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};
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/**
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* drm_debugfs_create_files - Initialize a given set of debugfs files for DRM
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* minor
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* @files: The array of files to create
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* @count: The number of files given
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* @root: DRI debugfs dir entry.
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* @minor: device minor number
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*
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* Create a given set of debugfs files represented by an array of
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* &struct drm_info_list in the given root directory. These files will be removed
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* automatically on drm_debugfs_cleanup().
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*/
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void drm_debugfs_create_files(const struct drm_info_list *files, int count,
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struct dentry *root, struct drm_minor *minor)
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{
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struct drm_device *dev = minor->dev;
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struct drm_info_node *tmp;
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int i;
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for (i = 0; i < count; i++) {
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u32 features = files[i].driver_features;
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if (features && !drm_core_check_all_features(dev, features))
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continue;
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tmp = kmalloc(sizeof(struct drm_info_node), GFP_KERNEL);
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if (tmp == NULL)
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continue;
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tmp->minor = minor;
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tmp->dent = debugfs_create_file(files[i].name,
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S_IFREG | S_IRUGO, root, tmp,
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&drm_debugfs_fops);
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tmp->info_ent = &files[i];
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mutex_lock(&minor->debugfs_lock);
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list_add(&tmp->list, &minor->debugfs_list);
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mutex_unlock(&minor->debugfs_lock);
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}
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}
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EXPORT_SYMBOL(drm_debugfs_create_files);
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int drm_debugfs_init(struct drm_minor *minor, int minor_id,
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struct dentry *root)
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{
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struct drm_device *dev = minor->dev;
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char name[64];
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INIT_LIST_HEAD(&minor->debugfs_list);
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mutex_init(&minor->debugfs_lock);
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sprintf(name, "%d", minor_id);
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minor->debugfs_root = debugfs_create_dir(name, root);
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drm_debugfs_create_files(drm_debugfs_list, DRM_DEBUGFS_ENTRIES,
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minor->debugfs_root, minor);
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if (drm_drv_uses_atomic_modeset(dev)) {
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drm_atomic_debugfs_init(minor);
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}
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if (drm_core_check_feature(dev, DRIVER_MODESET)) {
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drm_framebuffer_debugfs_init(minor);
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drm_client_debugfs_init(minor);
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}
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if (dev->driver->debugfs_init)
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dev->driver->debugfs_init(minor);
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return 0;
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}
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int drm_debugfs_remove_files(const struct drm_info_list *files, int count,
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struct drm_minor *minor)
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{
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struct list_head *pos, *q;
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struct drm_info_node *tmp;
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int i;
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mutex_lock(&minor->debugfs_lock);
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for (i = 0; i < count; i++) {
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list_for_each_safe(pos, q, &minor->debugfs_list) {
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tmp = list_entry(pos, struct drm_info_node, list);
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if (tmp->info_ent == &files[i]) {
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debugfs_remove(tmp->dent);
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list_del(pos);
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kfree(tmp);
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}
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}
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}
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mutex_unlock(&minor->debugfs_lock);
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return 0;
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}
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EXPORT_SYMBOL(drm_debugfs_remove_files);
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static void drm_debugfs_remove_all_files(struct drm_minor *minor)
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{
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struct drm_info_node *node, *tmp;
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mutex_lock(&minor->debugfs_lock);
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list_for_each_entry_safe(node, tmp, &minor->debugfs_list, list) {
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debugfs_remove(node->dent);
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list_del(&node->list);
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kfree(node);
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}
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mutex_unlock(&minor->debugfs_lock);
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}
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void drm_debugfs_cleanup(struct drm_minor *minor)
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{
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if (!minor->debugfs_root)
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return;
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drm_debugfs_remove_all_files(minor);
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debugfs_remove_recursive(minor->debugfs_root);
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minor->debugfs_root = NULL;
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}
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static int connector_show(struct seq_file *m, void *data)
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{
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struct drm_connector *connector = m->private;
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seq_printf(m, "%s\n", drm_get_connector_force_name(connector->force));
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return 0;
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}
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static int connector_open(struct inode *inode, struct file *file)
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{
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struct drm_connector *dev = inode->i_private;
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return single_open(file, connector_show, dev);
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}
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static ssize_t connector_write(struct file *file, const char __user *ubuf,
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size_t len, loff_t *offp)
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{
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struct seq_file *m = file->private_data;
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struct drm_connector *connector = m->private;
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char buf[12];
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if (len > sizeof(buf) - 1)
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return -EINVAL;
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if (copy_from_user(buf, ubuf, len))
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return -EFAULT;
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buf[len] = '\0';
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if (sysfs_streq(buf, "on"))
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connector->force = DRM_FORCE_ON;
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else if (sysfs_streq(buf, "digital"))
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connector->force = DRM_FORCE_ON_DIGITAL;
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else if (sysfs_streq(buf, "off"))
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connector->force = DRM_FORCE_OFF;
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else if (sysfs_streq(buf, "unspecified"))
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connector->force = DRM_FORCE_UNSPECIFIED;
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else
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return -EINVAL;
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return len;
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}
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static int edid_show(struct seq_file *m, void *data)
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{
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struct drm_connector *connector = m->private;
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struct drm_property_blob *edid = connector->edid_blob_ptr;
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if (connector->override_edid && edid)
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seq_write(m, edid->data, edid->length);
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return 0;
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}
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static int edid_open(struct inode *inode, struct file *file)
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{
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struct drm_connector *dev = inode->i_private;
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return single_open(file, edid_show, dev);
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}
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static ssize_t edid_write(struct file *file, const char __user *ubuf,
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size_t len, loff_t *offp)
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{
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struct seq_file *m = file->private_data;
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struct drm_connector *connector = m->private;
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char *buf;
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struct edid *edid;
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int ret;
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buf = memdup_user(ubuf, len);
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if (IS_ERR(buf))
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return PTR_ERR(buf);
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edid = (struct edid *) buf;
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if (len == 5 && !strncmp(buf, "reset", 5)) {
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connector->override_edid = false;
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ret = drm_connector_update_edid_property(connector, NULL);
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} else if (len < EDID_LENGTH ||
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EDID_LENGTH * (1 + edid->extensions) > len)
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ret = -EINVAL;
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else {
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connector->override_edid = false;
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ret = drm_connector_update_edid_property(connector, edid);
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if (!ret)
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connector->override_edid = true;
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}
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kfree(buf);
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return (ret) ? ret : len;
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}
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/*
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* Returns the min and max vrr vfreq through the connector's debugfs file.
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* Example usage: cat /sys/kernel/debug/dri/0/DP-1/vrr_range
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*/
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static int vrr_range_show(struct seq_file *m, void *data)
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{
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struct drm_connector *connector = m->private;
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if (connector->status != connector_status_connected)
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return -ENODEV;
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seq_printf(m, "Min: %u\n", (u8)connector->display_info.monitor_range.min_vfreq);
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seq_printf(m, "Max: %u\n", (u8)connector->display_info.monitor_range.max_vfreq);
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return 0;
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}
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DEFINE_SHOW_ATTRIBUTE(vrr_range);
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static const struct file_operations drm_edid_fops = {
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.owner = THIS_MODULE,
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.open = edid_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release,
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.write = edid_write
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};
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static const struct file_operations drm_connector_fops = {
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.owner = THIS_MODULE,
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.open = connector_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release,
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.write = connector_write
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};
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void drm_debugfs_connector_add(struct drm_connector *connector)
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{
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struct drm_minor *minor = connector->dev->primary;
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struct dentry *root;
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if (!minor->debugfs_root)
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return;
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root = debugfs_create_dir(connector->name, minor->debugfs_root);
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connector->debugfs_entry = root;
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/* force */
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debugfs_create_file("force", S_IRUGO | S_IWUSR, root, connector,
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&drm_connector_fops);
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/* edid */
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debugfs_create_file("edid_override", S_IRUGO | S_IWUSR, root, connector,
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&drm_edid_fops);
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/* vrr range */
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debugfs_create_file("vrr_range", S_IRUGO, root, connector,
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&vrr_range_fops);
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}
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void drm_debugfs_connector_remove(struct drm_connector *connector)
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{
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if (!connector->debugfs_entry)
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return;
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debugfs_remove_recursive(connector->debugfs_entry);
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connector->debugfs_entry = NULL;
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}
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void drm_debugfs_crtc_add(struct drm_crtc *crtc)
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{
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struct drm_minor *minor = crtc->dev->primary;
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struct dentry *root;
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char *name;
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name = kasprintf(GFP_KERNEL, "crtc-%d", crtc->index);
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if (!name)
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return;
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root = debugfs_create_dir(name, minor->debugfs_root);
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kfree(name);
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crtc->debugfs_entry = root;
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drm_debugfs_crtc_crc_add(crtc);
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}
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void drm_debugfs_crtc_remove(struct drm_crtc *crtc)
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|
{
|
|
debugfs_remove_recursive(crtc->debugfs_entry);
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|
crtc->debugfs_entry = NULL;
|
|
}
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#endif /* CONFIG_DEBUG_FS */
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