* [RFC PATCH v3] dmabuf-sync: Introduce buffer synchronization framework
From: Inki Dae @ 2013-06-19 9:10 UTC (permalink / raw)
To: dri-devel, linux-fbdev, linux-arm-kernel, linux-media
Cc: maarten.lankhorst, daniel, robdclark, kyungmin.park, myungjoo.ham,
yj44.cho, Inki Dae
In-Reply-To: <1371467722-665-1-git-send-email-inki.dae@samsung.com>
This patch adds a buffer synchronization framework based on DMA BUF[1]
and reservation[2] to use dma-buf resource, and based on ww-mutexes[3]
for lock mechanism.
The purpose of this framework is to provide not only buffer access control
to CPU and DMA but also easy-to-use interfaces for device drivers and
potentially user application (not implemented for user applications, yet).
And this framework can be used for all dma devices using system memory as
dma buffer, especially for most ARM based SoCs.
Changelog v3:
- remove cache operation relevant codes and update document file.
Changelog v2:
- use atomic_add_unless to avoid potential bug.
- add a macro for checking valid access type.
- code clean.
The mechanism of this framework has the following steps,
1. Register dmabufs to a sync object - A task gets a new sync object and
can add one or more dmabufs that the task wants to access.
This registering should be performed when a device context or an event
context such as a page flip event is created or before CPU accesses a shared
buffer.
dma_buf_sync_get(a sync object, a dmabuf);
2. Lock a sync object - A task tries to lock all dmabufs added in its own
sync object. Basically, the lock mechanism uses ww-mutex[1] to avoid dead
lock issue and for race condition between CPU and CPU, CPU and DMA, and DMA
and DMA. Taking a lock means that others cannot access all locked dmabufs
until the task that locked the corresponding dmabufs, unlocks all the locked
dmabufs.
This locking should be performed before DMA or CPU accesses these dmabufs.
dma_buf_sync_lock(a sync object);
3. Unlock a sync object - The task unlocks all dmabufs added in its own sync
object. The unlock means that the DMA or CPU accesses to the dmabufs have
been completed so that others may access them.
This unlocking should be performed after DMA or CPU has completed accesses
to the dmabufs.
dma_buf_sync_unlock(a sync object);
4. Unregister one or all dmabufs from a sync object - A task unregisters
the given dmabufs from the sync object. This means that the task dosen't
want to lock the dmabufs.
The unregistering should be performed after DMA or CPU has completed
accesses to the dmabufs or when dma_buf_sync_lock() is failed.
dma_buf_sync_put(a sync object, a dmabuf);
dma_buf_sync_put_all(a sync object);
The described steps may be summarized as:
get -> lock -> CPU or DMA access to a buffer/s -> unlock -> put
This framework includes the following two features.
1. read (shared) and write (exclusive) locks - A task is required to declare
the access type when the task tries to register a dmabuf;
READ, WRITE, READ DMA, or WRITE DMA.
The below is example codes,
struct dmabuf_sync *sync;
sync = dmabuf_sync_init(NULL, "test sync");
dmabuf_sync_get(sync, dmabuf, DMA_BUF_ACCESS_R);
...
And the below can be used as access types:
DMA_BUF_ACCESS_R - CPU will access a buffer for read.
DMA_BUF_ACCESS_W - CPU will access a buffer for read or write.
DMA_BUF_ACCESS_DMA_R - DMA will access a buffer for read
DMA_BUF_ACCESS_DMA_W - DMA will access a buffer for read or
write.
2. Mandatory resource releasing - a task cannot hold a lock indefinitely.
A task may never try to unlock a buffer after taking a lock to the buffer.
In this case, a timer handler to the corresponding sync object is called
in five (default) seconds and then the timed-out buffer is unlocked by work
queue handler to avoid lockups and to enforce resources of the buffer.
The below is how to use:
1. Allocate and Initialize a sync object:
struct dmabuf_sync *sync;
sync = dmabuf_sync_init(NULL, "test sync");
...
2. Add a dmabuf to the sync object when setting up dma buffer relevant
registers:
dmabuf_sync_get(sync, dmabuf, DMA_BUF_ACCESS_READ);
...
3. Lock all dmabufs of the sync object before DMA or CPU accesses
the dmabufs:
dmabuf_sync_lock(sync);
...
4. Now CPU or DMA can access all dmabufs locked in step 3.
5. Unlock all dmabufs added in a sync object after DMA or CPU access
to these dmabufs is completed:
dmabuf_sync_unlock(sync);
And call the following functions to release all resources,
dmabuf_sync_put_all(sync);
dmabuf_sync_fini(sync);
You can refer to actual example codes:
https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-exynos.git/
commit/?h=dmabuf-sync&id@30bdee9bab5841ad32faade528d04cc0c5fc94
https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-exynos.git/
commit/?h=dmabuf-sync&idla548e9ea9e865592719ef6b1cde58366af9f5c
[1] http://lwn.net/Articles/470339/
[2] http://lwn.net/Articles/532616/
[3] https://patchwork.kernel.org/patch/2625361/
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
---
Documentation/dma-buf-sync.txt | 199 ++++++++++++++++
drivers/base/Kconfig | 7 +
drivers/base/Makefile | 1 +
drivers/base/dmabuf-sync.c | 501 ++++++++++++++++++++++++++++++++++++++++
include/linux/dma-buf.h | 14 ++
include/linux/dmabuf-sync.h | 115 +++++++++
include/linux/reservation.h | 7 +
7 files changed, 844 insertions(+), 0 deletions(-)
create mode 100644 Documentation/dma-buf-sync.txt
create mode 100644 drivers/base/dmabuf-sync.c
create mode 100644 include/linux/dmabuf-sync.h
diff --git a/Documentation/dma-buf-sync.txt b/Documentation/dma-buf-sync.txt
new file mode 100644
index 0000000..134de7b
--- /dev/null
+++ b/Documentation/dma-buf-sync.txt
@@ -0,0 +1,199 @@
+ DMA Buffer Synchronization Framework
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+ Inki Dae
+ <inki dot dae at samsung dot com>
+ <daeinki at gmail dot com>
+
+This document is a guide for device-driver writers describing the DMA buffer
+synchronization API. This document also describes how to use the API to
+use buffer synchronization mechanism between DMA and DMA, CPU and DMA, and
+CPU and CPU.
+
+The DMA Buffer synchronization API provides buffer synchronization mechanism;
+i.e., buffer access control to CPU and DMA, and easy-to-use interfaces for
+device drivers and potentially user application (not implemented for user
+applications, yet). And this API can be used for all dma devices using system
+memory as dma buffer, especially for most ARM based SoCs.
+
+
+Motivation
+----------
+
+Buffer synchronization issue between DMA and DMA:
+ Sharing a buffer, a device cannot be aware of when the other device
+ will access the shared buffer: a device may access a buffer containing
+ wrong data if the device accesses the shared buffer while another
+ device is still accessing the shared buffer.
+ Therefore, a user process should have waited for the completion of DMA
+ access by another device before a device tries to access the shared
+ buffer.
+
+Buffer synchronization issue between CPU and DMA:
+ A user process should consider that when having to send a buffer, filled
+ by CPU, to a device driver for the device driver to access the buffer as
+ a input buffer while CPU and DMA are sharing the buffer.
+ This means that the user process needs to understand how the device
+ driver is worked. Hence, the conventional mechanism not only makes
+ user application complicated but also incurs performance overhead.
+
+Buffer synchronization issue between CPU and CPU:
+ In case that two processes share one buffer; shared with DMA also,
+ they may need some mechanism to allow process B to access the shared
+ buffer after the completion of CPU access by process A.
+ Therefore, process B should have waited for the completion of CPU access
+ by process A using the mechanism before trying to access the shared
+ buffer.
+
+What is the best way to solve these buffer synchronization issues?
+ We may need a common object that a device driver and a user process
+ notify the common object of when they try to access a shared buffer.
+ That way we could decide when we have to allow or not to allow for CPU
+ or DMA to access the shared buffer through the common object.
+ If so, what could become the common object? Right, that's a dma-buf[1].
+ Now we have already been using the dma-buf to share one buffer with
+ other drivers.
+
+
+Basic concept
+-------------
+
+The mechanism of this framework has the following steps,
+ 1. Register dmabufs to a sync object - A task gets a new sync object and
+ can add one or more dmabufs that the task wants to access.
+ This registering should be performed when a device context or an event
+ context such as a page flip event is created or before CPU accesses a shared
+ buffer.
+
+ dma_buf_sync_get(a sync object, a dmabuf);
+
+ 2. Lock a sync object - A task tries to lock all dmabufs added in its own
+ sync object. Basically, the lock mechanism uses ww-mutexes[2] to avoid dead
+ lock issue and for race condition between CPU and CPU, CPU and DMA, and DMA
+ and DMA. Taking a lock means that others cannot access all locked dmabufs
+ until the task that locked the corresponding dmabufs, unlocks all the locked
+ dmabufs.
+ This locking should be performed before DMA or CPU accesses these dmabufs.
+
+ dma_buf_sync_lock(a sync object);
+
+ 3. Unlock a sync object - The task unlocks all dmabufs added in its own sync
+ object. The unlock means that the DMA or CPU accesses to the dmabufs have
+ been completed so that others may access them.
+ This unlocking should be performed after DMA or CPU has completed accesses
+ to the dmabufs.
+
+ dma_buf_sync_unlock(a sync object);
+
+ 4. Unregister one or all dmabufs from a sync object - A task unregisters
+ the given dmabufs from the sync object. This means that the task dosen't
+ want to lock the dmabufs.
+ The unregistering should be performed after DMA or CPU has completed
+ accesses to the dmabufs or when dma_buf_sync_lock() is failed.
+
+ dma_buf_sync_put(a sync object, a dmabuf);
+ dma_buf_sync_put_all(a sync object);
+
+ The described steps may be summarized as:
+ get -> lock -> CPU or DMA access to a buffer/s -> unlock -> put
+
+This framework includes the following two features.
+ 1. read (shared) and write (exclusive) locks - A task is required to declare
+ the access type when the task tries to register a dmabuf;
+ READ, WRITE, READ DMA, or WRITE DMA.
+
+ The below is example codes,
+ struct dmabuf_sync *sync;
+
+ sync = dmabuf_sync_init(NULL, "test sync");
+
+ dmabuf_sync_get(sync, dmabuf, DMA_BUF_ACCESS_R);
+ ...
+
+ 2. Mandatory resource releasing - a task cannot hold a lock indefinitely.
+ A task may never try to unlock a buffer after taking a lock to the buffer.
+ In this case, a timer handler to the corresponding sync object is called
+ in five (default) seconds and then the timed-out buffer is unlocked by work
+ queue handler to avoid lockups and to enforce resources of the buffer.
+
+
+Access types
+------------
+
+DMA_BUF_ACCESS_R - CPU will access a buffer for read.
+DMA_BUF_ACCESS_W - CPU will access a buffer for read or write.
+DMA_BUF_ACCESS_DMA_R - DMA will access a buffer for read
+DMA_BUF_ACCESS_DMA_W - DMA will access a buffer for read or write.
+
+
+API set
+-------
+
+bool is_dmabuf_sync_supported(void)
+ - Check if dmabuf sync is supported or not.
+
+struct dmabuf_sync *dmabuf_sync_init(void *priv, const char *name)
+ - Allocate and initialize a new sync object. The caller can get a new
+ sync object for buffer synchronization. priv is used to set caller's
+ private data and name is the name of sync object.
+
+void dmabuf_sync_fini(struct dmabuf_sync *sync)
+ - Release all resources to the sync object.
+
+int dmabuf_sync_get(struct dmabuf_sync *sync, void *sync_buf,
+ unsigned int type)
+ - Add a dmabuf to a sync object. The caller can group multiple dmabufs
+ by calling this function several times. Internally, this function also
+ takes a reference to a dmabuf.
+
+void dmabuf_sync_put(struct dmabuf_sync *sync, struct dma_buf *dmabuf)
+ - Remove a given dmabuf from a sync object. Internally, this function
+ also release every reference to the given dmabuf.
+
+void dmabuf_sync_put_all(struct dmabuf_sync *sync)
+ - Remove all dmabufs added in a sync object. Internally, this function
+ also release every reference to the dmabufs of the sync object.
+
+int dmabuf_sync_lock(struct dmabuf_sync *sync)
+ - Lock all dmabufs added in a sync object. The caller should call this
+ function prior to CPU or DMA access to the dmabufs so that others can
+ not access the dmabufs. Internally, this function avoids dead lock
+ issue with ww-mutexes.
+
+int dmabuf_sync_unlock(struct dmabuf_sync *sync)
+ - Unlock all dmabufs added in a sync object. The caller should call
+ this function after CPU or DMA access to the dmabufs is completed so
+ that others can access the dmabufs.
+
+
+Tutorial
+--------
+
+1. Allocate and Initialize a sync object:
+ struct dmabuf_sync *sync;
+
+ sync = dmabuf_sync_init(NULL, "test sync");
+ ...
+
+2. Add a dmabuf to the sync object when setting up dma buffer relevant registers:
+ dmabuf_sync_get(sync, dmabuf, DMA_BUF_ACCESS_READ);
+ ...
+
+3. Lock all dmabufs of the sync object before DMA or CPU accesses the dmabufs:
+ dmabuf_sync_lock(sync);
+ ...
+
+4. Now CPU or DMA can access all dmabufs locked in step 3.
+
+5. Unlock all dmabufs added in a sync object after DMA or CPU access to these
+ dmabufs is completed:
+ dmabuf_sync_unlock(sync);
+
+ And call the following functions to release all resources,
+ dmabuf_sync_put_all(sync);
+ dmabuf_sync_fini(sync);
+
+
+References:
+[1] http://lwn.net/Articles/470339/
+[2] https://patchwork.kernel.org/patch/2625361/
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index 5ccf182..54a1d5a 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -212,6 +212,13 @@ config FENCE_TRACE
lockup related problems for dma-buffers shared across multiple
devices.
+config DMABUF_SYNC
+ bool "DMABUF Synchronization Framework"
+ depends on DMA_SHARED_BUFFER
+ help
+ This option enables dmabuf sync framework for buffer synchronization between
+ DMA and DMA, CPU and DMA, and CPU and CPU.
+
config CMA
bool "Contiguous Memory Allocator"
depends on HAVE_DMA_CONTIGUOUS && HAVE_MEMBLOCK
diff --git a/drivers/base/Makefile b/drivers/base/Makefile
index 8a55cb9..599f6c90 100644
--- a/drivers/base/Makefile
+++ b/drivers/base/Makefile
@@ -11,6 +11,7 @@ obj-y += power/
obj-$(CONFIG_HAS_DMA) += dma-mapping.o
obj-$(CONFIG_HAVE_GENERIC_DMA_COHERENT) += dma-coherent.o
obj-$(CONFIG_DMA_SHARED_BUFFER) += dma-buf.o fence.o reservation.o
+obj-$(CONFIG_DMABUF_SYNC) += dmabuf-sync.o
obj-$(CONFIG_ISA) += isa.o
obj-$(CONFIG_FW_LOADER) += firmware_class.o
obj-$(CONFIG_NUMA) += node.o
diff --git a/drivers/base/dmabuf-sync.c b/drivers/base/dmabuf-sync.c
new file mode 100644
index 0000000..7f3ac81
--- /dev/null
+++ b/drivers/base/dmabuf-sync.c
@@ -0,0 +1,501 @@
+/*
+ * Copyright (C) 2013 Samsung Electronics Co.Ltd
+ * Authors:
+ * Inki Dae <inki.dae@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
+
+#include <linux/dmabuf-sync.h>
+
+#define MAX_SYNC_TIMEOUT 5 /* Second. */
+
+int dmabuf_sync_enabled = 1;
+
+MODULE_PARM_DESC(enabled, "Check if dmabuf sync is supported or not");
+module_param_named(enabled, dmabuf_sync_enabled, int, 0444);
+
+static void dmabuf_sync_timeout_worker(struct work_struct *work)
+{
+ struct dmabuf_sync *sync = container_of(work, struct dmabuf_sync, work);
+ struct dmabuf_sync_object *sobj;
+
+ mutex_lock(&sync->lock);
+
+ list_for_each_entry(sobj, &sync->syncs, head) {
+ if (WARN_ON(!sobj->robj))
+ continue;
+
+ printk(KERN_WARNING "%s: timeout = 0x%x [type = %d, " \
+ "refcnt = %d, locked = %d]\n",
+ sync->name, (u32)sobj->dmabuf,
+ sobj->access_type,
+ atomic_read(&sobj->robj->shared_cnt),
+ sobj->robj->locked);
+
+ /* unlock only valid sync object. */
+ if (!sobj->robj->locked)
+ continue;
+
+ if (sobj->robj->shared &&
+ atomic_add_unless(&sobj->robj->shared_cnt, -1, 1))
+ continue;
+
+ ww_mutex_unlock(&sobj->robj->lock);
+
+ if (sobj->access_type & DMA_BUF_ACCESS_R)
+ printk(KERN_WARNING "%s: r-unlocked = 0x%x\n",
+ sync->name, (u32)sobj->dmabuf);
+ else
+ printk(KERN_WARNING "%s: w-unlocked = 0x%x\n",
+ sync->name, (u32)sobj->dmabuf);
+ }
+
+ sync->status = 0;
+ mutex_unlock(&sync->lock);
+
+ dmabuf_sync_put_all(sync);
+ dmabuf_sync_fini(sync);
+}
+
+static void dmabuf_sync_lock_timeout(unsigned long arg)
+{
+ struct dmabuf_sync *sync = (struct dmabuf_sync *)arg;
+
+ schedule_work(&sync->work);
+}
+
+static int dmabuf_sync_lock_objs(struct dmabuf_sync *sync,
+ struct ww_acquire_ctx *ctx)
+{
+ struct dmabuf_sync_object *contended_sobj = NULL;
+ struct dmabuf_sync_object *res_sobj = NULL;
+ struct dmabuf_sync_object *sobj = NULL;
+ int ret;
+
+ if (ctx)
+ ww_acquire_init(ctx, &reservation_ww_class);
+
+retry:
+ list_for_each_entry(sobj, &sync->syncs, head) {
+ if (WARN_ON(!sobj->robj))
+ continue;
+
+ /* Don't lock in case of read and read. */
+ if (sobj->robj->accessed_type & DMA_BUF_ACCESS_R &&
+ sobj->access_type & DMA_BUF_ACCESS_R) {
+ atomic_inc(&sobj->robj->shared_cnt);
+ sobj->robj->shared = true;
+ continue;
+ }
+
+ if (sobj = res_sobj) {
+ res_sobj = NULL;
+ continue;
+ }
+
+ ret = ww_mutex_lock(&sobj->robj->lock, ctx);
+ if (ret < 0) {
+ contended_sobj = sobj;
+
+ if (ret = -EDEADLK)
+ printk(KERN_WARNING"%s: deadlock = 0x%x\n",
+ sync->name, (u32)sobj->dmabuf);
+ goto err;
+ }
+
+ sobj->robj->locked = true;
+ }
+
+ if (ctx)
+ ww_acquire_done(ctx);
+
+ init_timer(&sync->timer);
+
+ sync->timer.data = (unsigned long)sync;
+ sync->timer.function = dmabuf_sync_lock_timeout;
+ sync->timer.expires = jiffies + (HZ * MAX_SYNC_TIMEOUT);
+
+ add_timer(&sync->timer);
+
+ return 0;
+
+err:
+ list_for_each_entry_continue_reverse(sobj, &sync->syncs, head) {
+ /* Don't need to unlock in case of read and read. */
+ if (atomic_add_unless(&sobj->robj->shared_cnt, -1, 1))
+ continue;
+
+ ww_mutex_unlock(&sobj->robj->lock);
+ sobj->robj->locked = false;
+ }
+
+ if (res_sobj) {
+ if (!atomic_add_unless(&res_sobj->robj->shared_cnt, -1, 1)) {
+ ww_mutex_unlock(&res_sobj->robj->lock);
+ res_sobj->robj->locked = false;
+ }
+ }
+
+ if (ret = -EDEADLK) {
+ ww_mutex_lock_slow(&contended_sobj->robj->lock, ctx);
+ res_sobj = contended_sobj;
+
+ goto retry;
+ }
+
+ if (ctx)
+ ww_acquire_fini(ctx);
+
+ return ret;
+}
+
+static void dmabuf_sync_unlock_objs(struct dmabuf_sync *sync,
+ struct ww_acquire_ctx *ctx)
+{
+ struct dmabuf_sync_object *sobj;
+
+ if (list_empty(&sync->syncs))
+ return;
+
+ mutex_lock(&sync->lock);
+
+ list_for_each_entry(sobj, &sync->syncs, head) {
+ if (sobj->robj->shared) {
+ if (atomic_add_unless(&sobj->robj->shared_cnt, -1 , 1))
+ continue;
+
+ ww_mutex_unlock(&sobj->robj->lock);
+ sobj->robj->shared = false;
+ sobj->robj->locked = false;
+ } else {
+ ww_mutex_unlock(&sobj->robj->lock);
+ sobj->robj->locked = false;
+ }
+ }
+
+ mutex_unlock(&sync->lock);
+
+ if (ctx)
+ ww_acquire_fini(ctx);
+
+ del_timer(&sync->timer);
+}
+
+/**
+ * is_dmabuf_sync_supported - Check if dmabuf sync is supported or not.
+ */
+bool is_dmabuf_sync_supported(void)
+{
+ return dmabuf_sync_enabled = 1;
+}
+EXPORT_SYMBOL(is_dmabuf_sync_supported);
+
+/**
+ * dmabuf_sync_init - Allocate and initialize a dmabuf sync.
+ *
+ * @priv: A device private data.
+ * @name: A sync object name.
+ *
+ * This function should be called when a device context or an event
+ * context such as a page flip event is created. And the created
+ * dmabuf_sync object should be set to the context.
+ * The caller can get a new sync object for buffer synchronization
+ * through this function.
+ */
+struct dmabuf_sync *dmabuf_sync_init(void *priv, const char *name)
+{
+ struct dmabuf_sync *sync;
+
+ sync = kzalloc(sizeof(*sync), GFP_KERNEL);
+ if (!sync)
+ return ERR_PTR(-ENOMEM);
+
+ strncpy(sync->name, name, ARRAY_SIZE(sync->name) - 1);
+
+ sync->priv = priv;
+ INIT_LIST_HEAD(&sync->syncs);
+ mutex_init(&sync->lock);
+ INIT_WORK(&sync->work, dmabuf_sync_timeout_worker);
+
+ return sync;
+}
+EXPORT_SYMBOL(dmabuf_sync_init);
+
+/**
+ * dmabuf_sync_fini - Release a given dmabuf sync.
+ *
+ * @sync: An object to dmabuf_sync structure.
+ *
+ * This function should be called if some operation is failed after
+ * dmabuf_sync_init call to release relevant resources, and after
+ * dmabuf_sync_unlock function is called.
+ */
+void dmabuf_sync_fini(struct dmabuf_sync *sync)
+{
+ if (WARN_ON(!sync))
+ return;
+
+ kfree(sync);
+}
+EXPORT_SYMBOL(dmabuf_sync_fini);
+
+/*
+ * dmabuf_sync_get_obj - Add a given object to syncs list.
+ *
+ * @sync: An object to dmabuf_sync structure.
+ * @dmabuf: An object to dma_buf structure.
+ * @type: A access type to a dma buf.
+ * The DMA_BUF_ACCESS_R means that this dmabuf could be accessed by
+ * others for read access. On the other hand, the DMA_BUF_ACCESS_W
+ * means that this dmabuf couldn't be accessed by others but would be
+ * accessed by caller's dma exclusively. And the DMA_BUF_ACCESS_DMA can be
+ * combined.
+ *
+ * This function creates and initializes a new dmabuf sync object and it adds
+ * the dmabuf sync object to syncs list to track and manage all dmabufs.
+ */
+static int dmabuf_sync_get_obj(struct dmabuf_sync *sync, struct dma_buf *dmabuf,
+ unsigned int type)
+{
+ struct dmabuf_sync_object *sobj;
+
+ if (!dmabuf->resv) {
+ WARN_ON(1);
+ return -EFAULT;
+ }
+
+ if (!IS_VALID_DMA_BUF_ACCESS_TYPE(type))
+ return -EINVAL;
+
+ if ((type & DMA_BUF_ACCESS_RW) = DMA_BUF_ACCESS_RW)
+ type &= ~DMA_BUF_ACCESS_R;
+
+ sobj = kzalloc(sizeof(*sobj), GFP_KERNEL);
+ if (!sobj) {
+ WARN_ON(1);
+ return -ENOMEM;
+ }
+
+ sobj->dmabuf = dmabuf;
+ sobj->robj = dmabuf->resv;
+
+ mutex_lock(&sync->lock);
+ list_add_tail(&sobj->head, &sync->syncs);
+ mutex_unlock(&sync->lock);
+
+ get_dma_buf(dmabuf);
+
+ sobj->access_type = type;
+
+ return 0;
+}
+
+/*
+ * dmabuf_sync_put_obj - Release a given sync object.
+ *
+ * @sync: An object to dmabuf_sync structure.
+ *
+ * This function should be called if some operation is failed after
+ * dmabuf_sync_get_obj call to release a given sync object.
+ */
+static void dmabuf_sync_put_obj(struct dmabuf_sync *sync,
+ struct dma_buf *dmabuf)
+{
+ struct dmabuf_sync_object *sobj;
+
+ mutex_lock(&sync->lock);
+
+ list_for_each_entry(sobj, &sync->syncs, head) {
+ if (sobj->dmabuf != dmabuf)
+ continue;
+
+ dma_buf_put(sobj->dmabuf);
+
+ list_del_init(&sobj->head);
+ kfree(sobj);
+ break;
+ }
+
+ if (list_empty(&sync->syncs))
+ sync->status = 0;
+
+ mutex_unlock(&sync->lock);
+}
+
+/*
+ * dmabuf_sync_put_objs - Release all sync objects of dmabuf_sync.
+ *
+ * @sync: An object to dmabuf_sync structure.
+ *
+ * This function should be called if some operation is failed after
+ * dmabuf_sync_get_obj call to release all sync objects.
+ */
+static void dmabuf_sync_put_objs(struct dmabuf_sync *sync)
+{
+ struct dmabuf_sync_object *sobj, *next;
+
+ mutex_lock(&sync->lock);
+
+ list_for_each_entry_safe(sobj, next, &sync->syncs, head) {
+ dma_buf_put(sobj->dmabuf);
+
+ list_del_init(&sobj->head);
+ kfree(sobj);
+ }
+
+ mutex_unlock(&sync->lock);
+
+ sync->status = 0;
+}
+
+/**
+ * dmabuf_sync_lock - lock all dmabufs added to syncs list.
+ *
+ * @sync: An object to dmabuf_sync structure.
+ *
+ * The caller should call this function prior to CPU or DMA access to
+ * the dmabufs so that others can not access the dmabufs.
+ * Internally, this function avoids dead lock issue with ww-mutex.
+ */
+int dmabuf_sync_lock(struct dmabuf_sync *sync)
+{
+ int ret;
+
+ if (!sync) {
+ WARN_ON(1);
+ return -EFAULT;
+ }
+
+ if (list_empty(&sync->syncs))
+ return -EINVAL;
+
+ if (sync->status != DMABUF_SYNC_GOT)
+ return -EINVAL;
+
+ ret = dmabuf_sync_lock_objs(sync, &sync->ctx);
+ if (ret < 0) {
+ WARN_ON(1);
+ return ret;
+ }
+
+ sync->status = DMABUF_SYNC_LOCKED;
+
+ return ret;
+}
+EXPORT_SYMBOL(dmabuf_sync_lock);
+
+/**
+ * dmabuf_sync_unlock - unlock all objects added to syncs list.
+ *
+ * @sync: An object to dmabuf_sync structure.
+ *
+ * The caller should call this function after CPU or DMA access to
+ * the dmabufs is completed so that others can access the dmabufs.
+ */
+int dmabuf_sync_unlock(struct dmabuf_sync *sync)
+{
+ if (!sync) {
+ WARN_ON(1);
+ return -EFAULT;
+ }
+
+ /* If current dmabuf sync object wasn't reserved then just return. */
+ if (sync->status != DMABUF_SYNC_LOCKED)
+ return -EAGAIN;
+
+ dmabuf_sync_unlock_objs(sync, &sync->ctx);
+
+ return 0;
+}
+EXPORT_SYMBOL(dmabuf_sync_unlock);
+
+/**
+ * dmabuf_sync_get - initialize reservation entry and update
+ * dmabuf sync.
+ *
+ * @sync: An object to dmabuf_sync structure.
+ * @sync_buf: A dma_buf object pointer that we want to be synchronized
+ * with others.
+ *
+ * This function should be called after dmabuf_sync_init function is called.
+ * The caller can group multiple dmabufs by calling this function several
+ * times. Internally, this function also takes a reference to a dmabuf.
+ */
+int dmabuf_sync_get(struct dmabuf_sync *sync, void *sync_buf, unsigned int type)
+{
+ int ret;
+
+ if (!sync || !sync_buf) {
+ WARN_ON(1);
+ return -EFAULT;
+ }
+
+ ret = dmabuf_sync_get_obj(sync, sync_buf, type);
+ if (ret < 0) {
+ WARN_ON(1);
+ return ret;
+ }
+
+ sync->status = DMABUF_SYNC_GOT;
+
+ return 0;
+}
+EXPORT_SYMBOL(dmabuf_sync_get);
+
+/**
+ * dmabuf_sync_put - Release a given dmabuf.
+ *
+ * @sync: An object to dmabuf_sync structure.
+ * @dmabuf: An object to dma_buf structure.
+ *
+ * This function should be called if some operation is failed after
+ * dmabuf_sync_get function is called to release the dmabuf, or
+ * dmabuf_sync_unlock function is called.
+ */
+void dmabuf_sync_put(struct dmabuf_sync *sync, struct dma_buf *dmabuf)
+{
+ if (!sync || !dmabuf) {
+ WARN_ON(1);
+ return;
+ }
+
+ if (list_empty(&sync->syncs))
+ return;
+
+ dmabuf_sync_put_obj(sync, dmabuf);
+}
+EXPORT_SYMBOL(dmabuf_sync_put);
+
+/**
+ * dmabuf_sync_put_all - Release all sync objects
+ *
+ * @sync: An object to dmabuf_sync structure.
+ *
+ * This function should be called if some operation is failed after
+ * dmabuf_sync_get function is called to release all sync objects, or
+ * dmabuf_sync_unlock function is called.
+ */
+void dmabuf_sync_put_all(struct dmabuf_sync *sync)
+{
+ if (!sync) {
+ WARN_ON(1);
+ return;
+ }
+
+ if (list_empty(&sync->syncs))
+ return;
+
+ dmabuf_sync_put_objs(sync);
+}
+EXPORT_SYMBOL(dmabuf_sync_put_all);
diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index 34cfbac..ae0c87b 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h
@@ -150,6 +150,20 @@ struct dma_buf_attachment {
void *priv;
};
+#define DMA_BUF_ACCESS_R 0x1
+#define DMA_BUF_ACCESS_W 0x2
+#define DMA_BUF_ACCESS_DMA 0x4
+#define DMA_BUF_ACCESS_RW (DMA_BUF_ACCESS_R | DMA_BUF_ACCESS_W)
+#define DMA_BUF_ACCESS_DMA_R (DMA_BUF_ACCESS_R | DMA_BUF_ACCESS_DMA)
+#define DMA_BUF_ACCESS_DMA_W (DMA_BUF_ACCESS_W | DMA_BUF_ACCESS_DMA)
+#define DMA_BUF_ACCESS_DMA_RW (DMA_BUF_ACCESS_DMA_R | DMA_BUF_ACCESS_DMA_W)
+#define IS_VALID_DMA_BUF_ACCESS_TYPE(t) (t = DMA_BUF_ACCESS_R || \
+ t = DMA_BUF_ACCESS_W || \
+ t = DMA_BUF_ACCESS_DMA_R || \
+ t = DMA_BUF_ACCESS_DMA_W || \
+ t = DMA_BUF_ACCESS_RW || \
+ t = DMA_BUF_ACCESS_DMA_RW)
+
/**
* get_dma_buf - convenience wrapper for get_file.
* @dmabuf: [in] pointer to dma_buf
diff --git a/include/linux/dmabuf-sync.h b/include/linux/dmabuf-sync.h
new file mode 100644
index 0000000..44c37de
--- /dev/null
+++ b/include/linux/dmabuf-sync.h
@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2013 Samsung Electronics Co.Ltd
+ * Authors:
+ * Inki Dae <inki.dae@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ */
+
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include <linux/dma-buf.h>
+#include <linux/reservation.h>
+
+enum dmabuf_sync_status {
+ DMABUF_SYNC_GOT = 1,
+ DMABUF_SYNC_LOCKED,
+};
+
+/*
+ * A structure for dmabuf_sync_object.
+ *
+ * @head: A list head to be added to syncs list.
+ * @robj: A reservation_object object.
+ * @dma_buf: A dma_buf object.
+ * @access_type: Indicate how a current task tries to access
+ * a given buffer.
+ */
+struct dmabuf_sync_object {
+ struct list_head head;
+ struct reservation_object *robj;
+ struct dma_buf *dmabuf;
+ unsigned int access_type;
+};
+
+/*
+ * A structure for dmabuf_sync.
+ *
+ * @syncs: A list head to sync object and this is global to system.
+ * @list: A list entry used as committed list node
+ * @lock: A mutex lock to current sync object.
+ * @ctx: A current context for ww mutex.
+ * @work: A work struct to release resources at timeout.
+ * @priv: A private data.
+ * @name: A string to dmabuf sync owner.
+ * @timer: A timer list to avoid lockup and release resources.
+ * @status: Indicate current status (DMABUF_SYNC_GOT or DMABUF_SYNC_LOCKED).
+ */
+struct dmabuf_sync {
+ struct list_head syncs;
+ struct list_head list;
+ struct mutex lock;
+ struct ww_acquire_ctx ctx;
+ struct work_struct work;
+ void *priv;
+ char name[64];
+ struct timer_list timer;
+ unsigned int status;
+};
+
+#ifdef CONFIG_DMABUF_SYNC
+extern bool is_dmabuf_sync_supported(void);
+
+extern struct dmabuf_sync *dmabuf_sync_init(void *priv, const char *name);
+
+extern void dmabuf_sync_fini(struct dmabuf_sync *sync);
+
+extern int dmabuf_sync_lock(struct dmabuf_sync *sync);
+
+extern int dmabuf_sync_unlock(struct dmabuf_sync *sync);
+
+extern int dmabuf_sync_get(struct dmabuf_sync *sync, void *sync_buf,
+ unsigned int type);
+
+extern void dmabuf_sync_put(struct dmabuf_sync *sync, struct dma_buf *dmabuf);
+
+extern void dmabuf_sync_put_all(struct dmabuf_sync *sync);
+
+#else
+static inline bool is_dmabuf_sync_supported(void) { return false; }
+
+static inline struct dmabuf_sync *dmabuf_sync_init(void *priv,
+ const char *names)
+{
+ return ERR_PTR(0);
+}
+
+static inline void dmabuf_sync_fini(struct dmabuf_sync *sync) { }
+
+static inline int dmabuf_sync_lock(struct dmabuf_sync *sync)
+{
+ return 0;
+}
+
+static inline int dmabuf_sync_unlock(struct dmabuf_sync *sync)
+{
+ return 0;
+}
+
+static inline int dmabuf_sync_get(struct dmabuf_sync *sync,
+ void *sync_buf,
+ unsigned int type)
+{
+ return 0;
+}
+
+static inline void dmabuf_sync_put(struct dmabuf_sync *sync,
+ struct dma_buf *dmabuf) { }
+
+static inline void dmabuf_sync_put_all(struct dmabuf_sync *sync) { }
+
+#endif
diff --git a/include/linux/reservation.h b/include/linux/reservation.h
index 80050e2..4310192 100644
--- a/include/linux/reservation.h
+++ b/include/linux/reservation.h
@@ -50,6 +50,11 @@ struct reservation_object {
struct fence *fence_excl;
struct fence **fence_shared;
u32 fence_shared_count, fence_shared_max;
+
+ atomic_t shared_cnt;
+ unsigned int accessed_type;
+ unsigned int shared;
+ unsigned int locked;
};
static inline void
@@ -60,6 +65,8 @@ reservation_object_init(struct reservation_object *obj)
obj->fence_shared_count = obj->fence_shared_max = 0;
obj->fence_shared = NULL;
obj->fence_excl = NULL;
+
+ atomic_set(&obj->shared_cnt, 1);
}
static inline void
--
1.7.5.4
^ permalink raw reply related
* DRM/KMS/FB: HDMI hotplug displays 1024x768 resolution instead of native mode
From: Jiada Wang @ 2013-06-19 7:37 UTC (permalink / raw)
To: linux-arm-kernel, airlied, linux-fbdev-devel; +Cc: Jiada Wang
Hi,
I am implementing HDMI hotplug feature for i.MX6 platform,
the basic function has already been done and works
But there is is an "issue",
When bootup system without HDMI cable attached, fbcon is initialised
with fbsize: 1024x768, after plug-in HDMI cable, I can see in debug log,
display's valid video_mode has been read via DDC, but in
drm_fb_helper_hotplug_event(), only size lower than
fb_helper->fb->width/fb_helper->fb->height, will be accepted,
So instead of the display's native mode, 1024x768 is displayed.
Is it correct DRM/fbdev behaviour?
Thanks,
Jiada
^ permalink raw reply
* Re: [PATCH 1/2] video: fbmem: Use 'const char' in fb_get_options()
From: Ville Syrjälä @ 2013-06-19 7:33 UTC (permalink / raw)
To: linux-fbdev
In-Reply-To: <1371561988-30989-1-git-send-email-fabio.estevam@freescale.com>
On Tue, Jun 18, 2013 at 10:26:27AM -0300, Fabio Estevam wrote:
> Commit d20d31748 (drm: Constify the pretty-print functions) causes the following
> build warning:
>
> drivers/gpu/drm/drm_fb_helper.c:127:3: warning: passing argument 1 of 'fb_get_options' discards 'const' qualifier from pointer target type [enabled by default]
>
> Let's change the first argument of fb_get_options from 'char *' to 'const char *'
> so that we can get rid of this warning.
I already sent the same patch alongside the drm constify patches. It
just needs to trickle back into the drm tree via the fbdev folks.
>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Cc: Dave Airlie <airlied@redhat.com>
> Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
> ---
> drivers/video/fbmem.c | 2 +-
> include/linux/fb.h | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c
> index 098bfc6..d8d5779 100644
> --- a/drivers/video/fbmem.c
> +++ b/drivers/video/fbmem.c
> @@ -1881,7 +1881,7 @@ static int ofonly __read_mostly;
> *
> * NOTE: Needed to maintain backwards compatibility
> */
> -int fb_get_options(char *name, char **option)
> +int fb_get_options(const char *name, char **option)
> {
> char *opt, *options = NULL;
> int retval = 0;
> diff --git a/include/linux/fb.h b/include/linux/fb.h
> index d49c60f..ffac70a 100644
> --- a/include/linux/fb.h
> +++ b/include/linux/fb.h
> @@ -624,7 +624,7 @@ extern void fb_pad_aligned_buffer(u8 *dst, u32 d_pitch, u8 *src, u32 s_pitch, u3
> extern void fb_set_suspend(struct fb_info *info, int state);
> extern int fb_get_color_depth(struct fb_var_screeninfo *var,
> struct fb_fix_screeninfo *fix);
> -extern int fb_get_options(char *name, char **option);
> +extern int fb_get_options(const char *name, char **option);
> extern int fb_new_modelist(struct fb_info *info);
>
> extern struct fb_info *registered_fb[FB_MAX];
> --
> 1.8.1.2
>
--
Ville Syrjälä
Intel OTC
^ permalink raw reply
* Re: [PATCH] build some drivers only when compile-testing
From: Tomi Valkeinen @ 2013-06-19 7:19 UTC (permalink / raw)
To: Jiri Slaby
Cc: Jeff Mahoney, Greg Kroah-Hartman, jirislaby, linux-kernel,
Andrew Morton, Linus Torvalds, Alexander Shishkin, linux-usb,
Florian Tobias Schandinat, linux-geode, linux-fbdev,
Richard Cochran, netdev, Ben Hutchings, Keller, Jacob E,
Michal Marek
In-Reply-To: <51C159F8.8090604@suse.cz>
[-- Attachment #1: Type: text/plain, Size: 1040 bytes --]
On 19/06/13 10:12, Jiri Slaby wrote:
> On 06/19/2013 09:10 AM, Tomi Valkeinen wrote:
>> On 17/06/13 23:05, Jiri Slaby wrote:
>>
>>> The last point I inclined to the Greg's argument to remove the
>>> EXPERT dependency.
>>>
>>> So currently I have what is attached... Comments?
>>
>> The patch looks a bit odd with the USB_CHIPIDEA_IMX parts. You're
>> not adding COMPILE_TEST there, but you're adding a totally new
>> config option, and also changing the Makefile.
>
> Look:
>
> +config USB_CHIPIDEA_IMX
> + bool "ChipIdea IMX support"
> + depends on OF_DEVICE && (ARM || COMPILE_TEST)
>
> COMPILE_TEST added here ----------------^^^^^^^^^^^^
My point was that you're not adding COMPILE_TEST to an existing config
option, you're creating a totally new config option.
As I said, that's probably ok, but it'd be nice to mention extra things
like that in the desc. The pedantic approach would be to do the makefile
and Kconfig change in an earlier patch, and then add only COMPILE_TEST.
Tomi
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^ permalink raw reply
* Re: [PATCH] build some drivers only when compile-testing
From: Jiri Slaby @ 2013-06-19 7:12 UTC (permalink / raw)
To: Tomi Valkeinen
Cc: Jeff Mahoney, Greg Kroah-Hartman, jirislaby, linux-kernel,
Andrew Morton, Linus Torvalds, Alexander Shishkin, linux-usb,
Florian Tobias Schandinat, linux-geode, linux-fbdev,
Richard Cochran, netdev, Ben Hutchings, Keller, Jacob E,
Michal Marek
In-Reply-To: <51C1595D.60706@ti.com>
On 06/19/2013 09:10 AM, Tomi Valkeinen wrote:
> On 17/06/13 23:05, Jiri Slaby wrote:
>
>> The last point I inclined to the Greg's argument to remove the
>> EXPERT dependency.
>>
>> So currently I have what is attached... Comments?
>
> The patch looks a bit odd with the USB_CHIPIDEA_IMX parts. You're
> not adding COMPILE_TEST there, but you're adding a totally new
> config option, and also changing the Makefile.
Look:
+config USB_CHIPIDEA_IMX
+ bool "ChipIdea IMX support"
+ depends on OF_DEVICE && (ARM || COMPILE_TEST)
COMPILE_TEST added here ----------------^^^^^^^^^^^^
--
js
suse labs
^ permalink raw reply
* Re: [PATCH] build some drivers only when compile-testing
From: Tomi Valkeinen @ 2013-06-19 7:10 UTC (permalink / raw)
To: Jiri Slaby
Cc: Jeff Mahoney, Greg Kroah-Hartman, jirislaby, linux-kernel,
Andrew Morton, Linus Torvalds, Alexander Shishkin, linux-usb,
Florian Tobias Schandinat, linux-geode, linux-fbdev,
Richard Cochran, netdev, Ben Hutchings, Keller, Jacob E,
Michal Marek
In-Reply-To: <51BF6BFF.7050705@suse.cz>
[-- Attachment #1: Type: text/plain, Size: 446 bytes --]
On 17/06/13 23:05, Jiri Slaby wrote:
> The last point I inclined to the Greg's argument to remove the EXPERT
> dependency.
>
> So currently I have what is attached... Comments?
The patch looks a bit odd with the USB_CHIPIDEA_IMX parts. You're not
adding COMPILE_TEST there, but you're adding a totally new config
option, and also changing the Makefile.
Maybe that's ok, but there's no mention about this in the desc.
Tomi
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^ permalink raw reply
* Re: [PATCH] build some drivers only when compile-testing
From: Jiri Slaby @ 2013-06-19 6:50 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: Jeff Mahoney, jirislaby, linux-kernel, Andrew Morton,
Linus Torvalds, Alexander Shishkin, linux-usb,
Florian Tobias Schandinat, linux-geode, linux-fbdev,
Richard Cochran, netdev, Ben Hutchings, Keller, Jacob E,
Michal Marek, tomi.valkeinen
In-Reply-To: <20130618160427.GE28961@kroah.com>
On 06/18/2013 06:04 PM, Greg Kroah-Hartman wrote:
>> So currently I have what is attached... Comments?
>
> Looks good to me, want me to queue it up through my char/misc driver
> tree for 3.11?
If there are no objections... Whoever picks that up, I would be happy 8-).
--
js
suse labs
^ permalink raw reply
* RE: [RFC PATCH v2] dmabuf-sync: Introduce buffer synchronization framework
From: Inki Dae @ 2013-06-19 5:45 UTC (permalink / raw)
To: linux-fbdev
In-Reply-To: <1371467722-665-1-git-send-email-inki.dae@samsung.com>
> -----Original Message-----
> From: Lucas Stach [mailto:l.stach@pengutronix.de]
> Sent: Tuesday, June 18, 2013 6:47 PM
> To: Inki Dae
> Cc: 'Russell King - ARM Linux'; 'linux-fbdev'; 'Kyungmin Park'; 'DRI
> mailing list'; 'myungjoo.ham'; 'YoungJun Cho'; linux-arm-
> kernel@lists.infradead.org; linux-media@vger.kernel.org
> Subject: Re: [RFC PATCH v2] dmabuf-sync: Introduce buffer synchronization
> framework
>
> Am Dienstag, den 18.06.2013, 18:04 +0900 schrieb Inki Dae:
> [...]
> >
> > > a display device driver. It shouldn't be used within a single driver
> > > as a means of passing buffers between userspace and kernel space.
> >
> > What I try to do is not really such ugly thing. What I try to do is to
> > notify that, when CPU tries to access a buffer , to kernel side through
> > dmabuf interface. So it's not really to send the buffer to kernel.
> >
> > Thanks,
> > Inki Dae
> >
> The most basic question about why you are trying to implement this sort
> of thing in the dma_buf framework still stands.
>
> Once you imported a dma_buf into your DRM driver it's a GEM object and
> you can and should use the native DRM ioctls to prepare/end a CPU access
> to this BO. Then internally to your driver you can use the dma_buf
> reservation/fence stuff to provide the necessary cross-device sync.
>
I don't really want that is used only for DRM drivers. We really need it for all other DMA devices; i.e., v4l2 based drivers. That is what I try to do. And my approach uses reservation to use dma-buf resources but not dma fence stuff anymore. However, I'm looking into Radeon DRM driver for why we need dma fence stuff, and how we can use it if needed.
Thanks,
Inki Dae
> Regards,
> Lucas
> --
> Pengutronix e.K. | Lucas Stach |
> Industrial Linux Solutions | http://www.pengutronix.de/ |
> Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-5076 |
> Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
^ permalink raw reply
* Re: [PATCH v2 1/2] video: fbmem: Use 'const char' in fb_get_options()
From: David Airlie @ 2013-06-18 23:00 UTC (permalink / raw)
To: linux-fbdev
In-Reply-To: <1371568723-27486-1-git-send-email-fabio.estevam@freescale.com>
----- Original Message -----
> From: "Fabio Estevam" <fabio.estevam@freescale.com>
> To: plagnioj@jcrosoft.com
> Cc: linux-fbdev@vger.kernel.org, festevam@gmail.com, geert@linux-m68k.org, "Fabio Estevam"
> <fabio.estevam@freescale.com>, "Ville Syrjälä" <ville.syrjala@linux.intel.com>, "Daniel Vetter"
> <daniel.vetter@ffwll.ch>, "Dave Airlie" <airlied@redhat.com>
> Sent: Wednesday, 19 June, 2013 1:18:42 AM
> Subject: [PATCH v2 1/2] video: fbmem: Use 'const char' in fb_get_options()
>
> Commit d20d31748 (drm: Constify the pretty-print functions) causes the
> following
> build warning:
This patch should already be merged into the fbdev tree, at least the maintainer said it was, hence why I didn't merge it into
my drm-next tree.
Is the fbdev queue not in the drm-next?
Dave.
^ permalink raw reply
* Re: [PATCH] build some drivers only when compile-testing
From: Greg Kroah-Hartman @ 2013-06-18 16:04 UTC (permalink / raw)
To: Jiri Slaby
Cc: Jeff Mahoney, jirislaby, linux-kernel, Andrew Morton,
Linus Torvalds, Alexander Shishkin, linux-usb,
Florian Tobias Schandinat, linux-geode, linux-fbdev,
Richard Cochran, netdev, Ben Hutchings, Keller, Jacob E,
Michal Marek, tomi.valkeinen
In-Reply-To: <51BF6BFF.7050705@suse.cz>
On Mon, Jun 17, 2013 at 10:05:19PM +0200, Jiri Slaby wrote:
> On 05/23/2013 05:09 AM, Jeff Mahoney wrote:
> > On 5/22/13 10:23 PM, Greg Kroah-Hartman wrote:
> >> On Wed, May 22, 2013 at 11:18:46AM +0200, Jiri Slaby wrote:
> >>> Some drivers can be built on more platforms than they run on. This
> >>> causes users and distributors packaging burden when they have to
> >>> manually deselect some drivers from their allmodconfigs. Or sometimes
> >>> it is even impossible to disable the drivers without patching the
> >>> kernel.
> >>>
> >>> Introduce a new config option COMPILE_TEST and make all those drivers
> >>> to depend on the platform they run on, or on the COMPILE_TEST option.
> >>> Now, when users/distributors choose COMPILE_TEST=n they will not have
> >>> the drivers in their allmodconfig setups, but developers still can
> >>> compile-test them with COMPILE_TEST=y.
> >>
> >> I understand the urge, and it's getting hard for distros to handle these
> >> drivers that just don't work on other architectures, but it's really
> >> valuable to ensure that they build properly, for those of us that don't
> >> have many/any cross compilers set up.
>
> But this is exactly what COMPILE_TEST will give us when set to "y", or
> am I missing something?
>
> >>> Now the drivers where we use this new option:
> >>> * PTP_1588_CLOCK_PCH: The PCH EG20T is only compatible with Intel Atom
> >>> processors so it should depend on x86.
> >>> * FB_GEODE: Geode is 32-bit only so only enable it for X86_32.
> >>> * USB_CHIPIDEA_IMX: The OF_DEVICE dependency will be met on powerpc
> >>> systems -- which do not actually support the hardware via that
> >>> method.
> >>
> >> This seems ripe to start to get really messy, really quickly. Shouldn't
> >> "default configs" handle if this "should" be enabled for a platform or
> >> not, and let the rest of us just build them with no problems?
> >
> > If every time a new Kconfig option is added, corresponding default
> > config updates come with it, sure. I just don't see that happening,
> > especially when it can be done much more clearly in the Kconfig while
> > the developer is writing the driver.
> >
> >> What problems is this causing you? Are you running out of space in
> >> kernel packages with drivers that will never be actually used?
> >
> > Wasted build resources. Wasted disk space on /every/ system the kernel
> > package is installed on. We're all trying to pare down the kernel
> > packages to eliminate wasted space and doing it manually means a bunch
> > of research, sometimes with incorrect assumptions about the results,
> > needs to be done by someone not usually associated with that code. That
> > research gets repeated by people maintaining kernel packages for pretty
> > much every distro.
>
> I second all the above.
>
> >>> +config COMPILE_TEST
> >>> + bool "Compile also drivers which will not load" if EXPERT
> >>
> >> EXPERT is getting to be the "let's hide it here" option, isn't it...
> >>
> >> I don't know, if no one else strongly objects, I can be convinced that
> >> this is needed, but so far, I don't see why it really is, or what this
> >> is going to help with.
> >
> > I'm not convinced adding a || COMPILE_TEST option to every driver that
> > may be arch specific is the best way to go either. Perhaps adding a new
> > Kconfig verb called "archdepends on" or something that will evaluate as
> > true if COMPILE_TEST is enabled but will evaluate the conditional if
> > not. *waves hands*
>
> Sam Ravnborg (the kconfig ex-maintainer) once wrote that he doesn't want
> to extend the kconfig language for this purpose (which I support). That
> a config option is fine and sufficient in this case [1]. Except he
> called the config option "SHOW_ALL_DRIVERS". Adding the current
> maintainer to CCs ;).
>
> [1] http://comments.gmane.org/gmane.linux.kbuild.devel/9829
>
> The last point I inclined to the Greg's argument to remove the EXPERT
> dependency.
>
> So currently I have what is attached... Comments?
Looks good to me, want me to queue it up through my char/misc driver
tree for 3.11?
thanks,
greg k-h
^ permalink raw reply
* [PATCH v2 2/2] i915: i915_gem: Print a size_t with %z
From: Fabio Estevam @ 2013-06-18 15:18 UTC (permalink / raw)
To: plagnioj
Cc: Fabio Estevam, linux-fbdev, Daniel Vetter, intel-gfx, geert,
Dave Airlie, festevam
In-Reply-To: <1371568723-27486-1-git-send-email-fabio.estevam@freescale.com>
Fix the following build warning:
drivers/gpu/drm/i915/i915_gem.c:3129:3: warning: format '%ld' expects argument of type 'long int', but argument 5 has type 'size_t' [-Wformat]
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: <intel-gfx@lists.freedesktop.org>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
---
Changes since v1:
- Use %zu instead of %zd, since size_t is unsigned
drivers/gpu/drm/i915/i915_gem.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 6e469e6..d497ca5 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3126,7 +3126,7 @@ i915_gem_object_bind_to_gtt(struct drm_i915_gem_object *obj,
* before evicting everything in a vain attempt to find space.
*/
if (obj->base.size > gtt_max) {
- DRM_ERROR("Attempting to bind an object larger than the aperture: object=%zd > %s aperture=%ld\n",
+ DRM_ERROR("Attempting to bind an object larger than the aperture: object=%zd > %s aperture=%zu\n",
obj->base.size,
map_and_fenceable ? "mappable" : "total",
gtt_max);
--
1.8.1.2
^ permalink raw reply related
* [PATCH v2 1/2] video: fbmem: Use 'const char' in fb_get_options()
From: Fabio Estevam @ 2013-06-18 15:18 UTC (permalink / raw)
To: linux-fbdev
Commit d20d31748 (drm: Constify the pretty-print functions) causes the following
build warning:
drivers/gpu/drm/drm_fb_helper.c:127:3: warning: passing argument 1 of 'fb_get_options' discards 'const' qualifier from pointer target type [enabled by default]
Let's change the first argument of fb_get_options from 'char *' to 'const char *'
so that we can get rid of this warning.
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
---
Changes since v1:
- None
drivers/video/fbmem.c | 2 +-
include/linux/fb.h | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c
index 098bfc6..d8d5779 100644
--- a/drivers/video/fbmem.c
+++ b/drivers/video/fbmem.c
@@ -1881,7 +1881,7 @@ static int ofonly __read_mostly;
*
* NOTE: Needed to maintain backwards compatibility
*/
-int fb_get_options(char *name, char **option)
+int fb_get_options(const char *name, char **option)
{
char *opt, *options = NULL;
int retval = 0;
diff --git a/include/linux/fb.h b/include/linux/fb.h
index d49c60f..ffac70a 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -624,7 +624,7 @@ extern void fb_pad_aligned_buffer(u8 *dst, u32 d_pitch, u8 *src, u32 s_pitch, u3
extern void fb_set_suspend(struct fb_info *info, int state);
extern int fb_get_color_depth(struct fb_var_screeninfo *var,
struct fb_fix_screeninfo *fix);
-extern int fb_get_options(char *name, char **option);
+extern int fb_get_options(const char *name, char **option);
extern int fb_new_modelist(struct fb_info *info);
extern struct fb_info *registered_fb[FB_MAX];
--
1.8.1.2
^ permalink raw reply related
* Re: [PATCH 2/2] i915: i915_gem: Print a size_t with %z
From: Geert Uytterhoeven @ 2013-06-18 14:53 UTC (permalink / raw)
To: Fabio Estevam
Cc: Linux Fbdev development list, Jean-Christophe PLAGNIOL-VILLARD,
Intel Graphics Development, Daniel Vetter, Dave Airlie,
Fabio Estevam
In-Reply-To: <1371561988-30989-2-git-send-email-fabio.estevam@freescale.com>
On Tue, Jun 18, 2013 at 3:26 PM, Fabio Estevam
<fabio.estevam@freescale.com> wrote:
> drivers/gpu/drm/i915/i915_gem.c:3129:3: warning: format '%ld' expects argument of type 'long int', but argument 5 has type 'size_t' [-Wformat]
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -3126,7 +3126,7 @@ i915_gem_object_bind_to_gtt(struct drm_i915_gem_object *obj,
> * before evicting everything in a vain attempt to find space.
> */
> if (obj->base.size > gtt_max) {
> - DRM_ERROR("Attempting to bind an object larger than the aperture: object=%zd > %s aperture=%ld\n",
> + DRM_ERROR("Attempting to bind an object larger than the aperture: object=%zd > %s aperture=%zd\n",
size_t is unsigned, so you better change it to %zu.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
^ permalink raw reply
* [PATCH linux-next] fb: make fp_get_options name argument const
From: Vincent Stehlé @ 2013-06-18 14:23 UTC (permalink / raw)
To: linux-next, linux-fbdev
Cc: Vincent Stehlé, Jean-Christophe Plagniol-Villard,
Tomi Valkeinen, Dave Airlie, trivial
drm_get_connector_name now returns a const value, which causes the following
compilation warning:
drivers/gpu/drm/drm_fb_helper.c: In function ‘drm_fb_helper_parse_command_line’:
drivers/gpu/drm/drm_fb_helper.c:127:3: warning: passing argument 1 of ‘fb_get_options’ discards ‘const’ qualifier from pointer target type [enabled by default]
In file included from drivers/gpu/drm/drm_fb_helper.c:35:0:
include/linux/fb.h:627:12: note: expected ‘char *’ but argument is of type ‘const char *’
As fb_get_options uses its name argument as read only, make it const. This
fixes the aforementioned compilation warning.
Signed-off-by: Vincent Stehlé <vincent.stehle@freescale.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: trivial@kernel.org
---
Hi,
I remarked this warning while building linux-next with imx_v6_v7_defconfig.
Is changing fb_get_options prototype "permitted", please?
Best regards,
V.
drivers/video/fbmem.c | 2 +-
include/linux/fb.h | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c
index 098bfc6..d8d5779 100644
--- a/drivers/video/fbmem.c
+++ b/drivers/video/fbmem.c
@@ -1881,7 +1881,7 @@ static int ofonly __read_mostly;
*
* NOTE: Needed to maintain backwards compatibility
*/
-int fb_get_options(char *name, char **option)
+int fb_get_options(const char *name, char **option)
{
char *opt, *options = NULL;
int retval = 0;
diff --git a/include/linux/fb.h b/include/linux/fb.h
index d49c60f..ffac70a 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -624,7 +624,7 @@ extern void fb_pad_aligned_buffer(u8 *dst, u32 d_pitch, u8 *src, u32 s_pitch, u3
extern void fb_set_suspend(struct fb_info *info, int state);
extern int fb_get_color_depth(struct fb_var_screeninfo *var,
struct fb_fix_screeninfo *fix);
-extern int fb_get_options(char *name, char **option);
+extern int fb_get_options(const char *name, char **option);
extern int fb_new_modelist(struct fb_info *info);
extern struct fb_info *registered_fb[FB_MAX];
--
1.7.10.4
^ permalink raw reply related
* [PATCH 2/2] i915: i915_gem: Print a size_t with %z
From: Fabio Estevam @ 2013-06-18 13:26 UTC (permalink / raw)
To: plagnioj
Cc: Fabio Estevam, linux-fbdev, Daniel Vetter, intel-gfx, Dave Airlie,
festevam
In-Reply-To: <1371561988-30989-1-git-send-email-fabio.estevam@freescale.com>
Fix the following build warning:
drivers/gpu/drm/i915/i915_gem.c:3129:3: warning: format '%ld' expects argument of type 'long int', but argument 5 has type 'size_t' [-Wformat]
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: <intel-gfx@lists.freedesktop.org>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
---
drivers/gpu/drm/i915/i915_gem.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 6e469e6..d497ca5 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3126,7 +3126,7 @@ i915_gem_object_bind_to_gtt(struct drm_i915_gem_object *obj,
* before evicting everything in a vain attempt to find space.
*/
if (obj->base.size > gtt_max) {
- DRM_ERROR("Attempting to bind an object larger than the aperture: object=%zd > %s aperture=%ld\n",
+ DRM_ERROR("Attempting to bind an object larger than the aperture: object=%zd > %s aperture=%zd\n",
obj->base.size,
map_and_fenceable ? "mappable" : "total",
gtt_max);
--
1.8.1.2
^ permalink raw reply related
* [PATCH 1/2] video: fbmem: Use 'const char' in fb_get_options()
From: Fabio Estevam @ 2013-06-18 13:26 UTC (permalink / raw)
To: linux-fbdev
Commit d20d31748 (drm: Constify the pretty-print functions) causes the following
build warning:
drivers/gpu/drm/drm_fb_helper.c:127:3: warning: passing argument 1 of 'fb_get_options' discards 'const' qualifier from pointer target type [enabled by default]
Let's change the first argument of fb_get_options from 'char *' to 'const char *'
so that we can get rid of this warning.
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
---
drivers/video/fbmem.c | 2 +-
include/linux/fb.h | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c
index 098bfc6..d8d5779 100644
--- a/drivers/video/fbmem.c
+++ b/drivers/video/fbmem.c
@@ -1881,7 +1881,7 @@ static int ofonly __read_mostly;
*
* NOTE: Needed to maintain backwards compatibility
*/
-int fb_get_options(char *name, char **option)
+int fb_get_options(const char *name, char **option)
{
char *opt, *options = NULL;
int retval = 0;
diff --git a/include/linux/fb.h b/include/linux/fb.h
index d49c60f..ffac70a 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -624,7 +624,7 @@ extern void fb_pad_aligned_buffer(u8 *dst, u32 d_pitch, u8 *src, u32 s_pitch, u3
extern void fb_set_suspend(struct fb_info *info, int state);
extern int fb_get_color_depth(struct fb_var_screeninfo *var,
struct fb_fix_screeninfo *fix);
-extern int fb_get_options(char *name, char **option);
+extern int fb_get_options(const char *name, char **option);
extern int fb_new_modelist(struct fb_info *info);
extern struct fb_info *registered_fb[FB_MAX];
--
1.8.1.2
^ permalink raw reply related
* Re: [RFC PATCH v2] dmabuf-sync: Introduce buffer synchronization framework
From: Russell King - ARM Linux @ 2013-06-18 10:46 UTC (permalink / raw)
To: Daniel Vetter
Cc: Inki Dae, Maarten Lankhorst, linux-fbdev, Kyungmin Park,
DRI mailing list, Rob Clark, myungjoo.ham, YoungJun Cho,
linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org
In-Reply-To: <CAKMK7uECS=eqNB-Ud6s=NvdYMPfxgJaGPbUx9hANfP6kb02j_w@mail.gmail.com>
On Tue, Jun 18, 2013 at 09:00:16AM +0200, Daniel Vetter wrote:
> On Mon, Jun 17, 2013 at 04:42:37PM +0100, Russell King - ARM Linux wrote:
> > What we need is something along the lines of:
> > (a) dma_buf_map_attachment() _not_ to map the scatterlist for DMA.
> > or
> > (b) drm_gem_prime_import() not to call dma_buf_map_attachment() at all.
>
> I strongly vote for (b) (plus adding a dma_buf_map_sync interface to allow
> syncing to other devices/cpu whithout dropping the dma mappings). At least
> that's been the idea behind things, but currently all (x86-based) drm
> drivers cut corners here massively.
>
> Aside: The entire reason behind hiding the dma map step in the dma-buf
> attachment is to allow drivers to expose crazy iommus (e.g. the tiler unit
> on omap) to other devices. So imo (a) isn't the right choice.
That's why I also talk below about adding the dma_buf_map/sync callbacks
below, so that a dma_buf implementation can do whatever is necessary with
the sg at the point of use.
However, you are correct that this should be unnecessary, as DRM should
only be calling dma_buf_map_attachment() when it needs to know about the
memory behind the object. The problem is that people will cache that
information - it also may be expensive to setup for the dma_buf - as it
involves counting the number of pages, memory allocation, and maybe
obtaining the set of pages from shmem.
With (a) plus the callbacks below, it means that step is only performed
once, and then the DMA API part is entirely separate - we can have our
cake and eat it in that regard.
> > Note: the existing stuff does have the nice side effect of being able
> > to pass buffers which do not have a struct page * associated with them
> > through the dma_buf API - I think we can still preserve that by having
> > dma_buf provide a couple of new APIs to do the SG list map/sync/unmap,
> > but in any case we need to fix the existing API so that:
> >
> > dma_buf_map_attachment() becomes dma_buf_get_sg()
> > dma_buf_unmap_attachment() becomes dma_buf_put_sg()
> >
> > both getting rid of the DMA direction argument, and then we have four
> > new dma_buf calls:
> >
> > dma_buf_map_sg()
> > dma_buf_unmap_sg()
> > dma_buf_sync_sg_for_cpu()
> > dma_buf_sync_sg_for_device()
> >
> > which do the actual sg map/unmap via the DMA API *at the appropriate
> > time for DMA*.
>
> Hm, my idea was to just add a dma_buf_sync_attchment for the device side
> syncing, since the cpu access stuff is already bracketed with the
> begin/end cpu access stuff. We might need a sync_for_cpu or so for mmap,
> but imo mmap support for dma_buf is a bit insane anyway, so I don't care
> too much about it.
>
> Since such dma mappings would be really longstanding in most cases anyway
> drivers could just map with BIDIRECTIONAL and do all the real flushing
> with the new sync stuff.
Note that the DMA API debug doesn't allow you to change the direction
argument on an existing mapping (neither should it, again this is
documented in the DMA API stuff in Documentation/). This is where you
would need the complete set of four functions I mention above which
reflect the functionality of the DMA API.
The dma_buf implementation doesn't _have_ to implement them if they
are no-ops - for example, your dma_buf sg array contains DMA pointers,
and the memory is already coherent in some way (for example, it's a
separate chunk of memory which isn't part of system RAM.)
^ permalink raw reply
* Re: [RFC PATCH v2] dmabuf-sync: Introduce buffer synchronization framework
From: Lucas Stach @ 2013-06-18 9:47 UTC (permalink / raw)
To: Inki Dae
Cc: 'Russell King - ARM Linux', 'linux-fbdev',
'Kyungmin Park', 'DRI mailing list',
'myungjoo.ham', 'YoungJun Cho', linux-arm-kernel,
linux-media
In-Reply-To: <008a01ce6c02$e00a9f50$a01fddf0$%dae@samsung.com>
Am Dienstag, den 18.06.2013, 18:04 +0900 schrieb Inki Dae:
[...]
>
> > a display device driver. It shouldn't be used within a single driver
> > as a means of passing buffers between userspace and kernel space.
>
> What I try to do is not really such ugly thing. What I try to do is to
> notify that, when CPU tries to access a buffer , to kernel side through
> dmabuf interface. So it's not really to send the buffer to kernel.
>
> Thanks,
> Inki Dae
>
The most basic question about why you are trying to implement this sort
of thing in the dma_buf framework still stands.
Once you imported a dma_buf into your DRM driver it's a GEM object and
you can and should use the native DRM ioctls to prepare/end a CPU access
to this BO. Then internally to your driver you can use the dma_buf
reservation/fence stuff to provide the necessary cross-device sync.
Regards,
Lucas
--
Pengutronix e.K. | Lucas Stach |
Industrial Linux Solutions | http://www.pengutronix.de/ |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-5076 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
^ permalink raw reply
* Re: [RFC PATCH v2] dmabuf-sync: Introduce buffer synchronization framework
From: Russell King - ARM Linux @ 2013-06-18 9:38 UTC (permalink / raw)
To: Inki Dae
Cc: 'Maarten Lankhorst', 'linux-fbdev',
'Kyungmin Park', 'DRI mailing list',
'Rob Clark', 'myungjoo.ham',
'YoungJun Cho', 'Daniel Vetter', linux-arm-kernel,
linux-media
In-Reply-To: <008a01ce6c02$e00a9f50$a01fddf0$%dae@samsung.com>
On Tue, Jun 18, 2013 at 06:04:44PM +0900, Inki Dae wrote:
>
>
> > -----Original Message-----
> > From: Russell King - ARM Linux [mailto:linux@arm.linux.org.uk]
> > Sent: Tuesday, June 18, 2013 5:43 PM
> > To: Inki Dae
> > Cc: 'Maarten Lankhorst'; 'linux-fbdev'; 'Kyungmin Park'; 'DRI mailing
> > list'; 'Rob Clark'; 'myungjoo.ham'; 'YoungJun Cho'; 'Daniel Vetter';
> > linux-arm-kernel@lists.infradead.org; linux-media@vger.kernel.org
> > Subject: Re: [RFC PATCH v2] dmabuf-sync: Introduce buffer synchronization
> > framework
> >
> > On Tue, Jun 18, 2013 at 02:27:40PM +0900, Inki Dae wrote:
> > > So I'd like to ask for other DRM maintainers. How do you think about it?
> > it
> > > seems like that Intel DRM (maintained by Daniel), OMAP DRM (maintained
> > by
> > > Rob) and GEM CMA helper also have same issue Russell pointed out. I
> > think
> > > not only the above approach but also the performance is very important.
> >
> > CMA uses coherent memory to back their buffers, though that might not be
> > true of memory obtained from other drivers via dma_buf. Plus, there is
> > no support in the CMA helper for exporting or importng these buffers.
> >
>
> It's not so. Please see Dave's drm next. recently dmabuf support for the CMA
> helper has been merged to there.
The point stands: CMA is DMA coherent memory. It doesn't need and must
never be dma-map-sg'd or dma-sync'd or dma-unmap'd.
^ permalink raw reply
* Re: [PATCH] build some drivers only when compile-testing
From: Jiri Slaby @ 2013-06-18 9:21 UTC (permalink / raw)
To: balbi, Michal Marek
Cc: Jeff Mahoney, Greg Kroah-Hartman, jirislaby, linux-kernel,
Andrew Morton, Linus Torvalds, Alexander Shishkin, linux-usb,
Florian Tobias Schandinat, linux-geode, linux-fbdev,
Richard Cochran, netdev, Ben Hutchings, Keller, Jacob E,
tomi.valkeinen
In-Reply-To: <20130618085154.GN5461@arwen.pp.htv.fi>
On 06/18/2013 10:51 AM, Felipe Balbi wrote:
> right, but my argument is that I rather not have either. Depend on
> PCI if you us PCI, depend on EXTCON if you use extcon, but no
> driver should have an ARCH dependency. Specially since it lets
> people include mach/* and asm/* headers because "it doesn't break
> compilation for anyone".
The argument is elsewhere. If I understand correctly, Kconfig is for
users, not to be hi-jacked by kernel developers. And users should not
really care about our development processes, cross compilations or
whatever bells and whistles we use. They just don't want to see
drivers which they have no way to *use*, they indeed don't care
whether some more compile at all. We do not want every kernel packager
for every distro out in the wild, to go through all the help texts, to
see whether they should compile and package a driver or not. It's a
tedious work and this option would save time to the packagers.
Try to package and maintain a kernel for a distribution, you will find
out what a cool and surprising work that is...
In the best case I would vote for hard dependencies as cross-compilers
are easy to obtain and set up nowadays. But well, we still want to
("cross") compile drivers, so let's add COMPILE_TEST and use that to
save time to automatic builds.
--
js
suse labs
^ permalink raw reply
* RE: [RFC PATCH v2] dmabuf-sync: Introduce buffer synchronization framework
From: Inki Dae @ 2013-06-18 9:04 UTC (permalink / raw)
To: linux-fbdev
In-Reply-To: <1371467722-665-1-git-send-email-inki.dae@samsung.com>
> -----Original Message-----
> From: Russell King - ARM Linux [mailto:linux@arm.linux.org.uk]
> Sent: Tuesday, June 18, 2013 5:43 PM
> To: Inki Dae
> Cc: 'Maarten Lankhorst'; 'linux-fbdev'; 'Kyungmin Park'; 'DRI mailing
> list'; 'Rob Clark'; 'myungjoo.ham'; 'YoungJun Cho'; 'Daniel Vetter';
> linux-arm-kernel@lists.infradead.org; linux-media@vger.kernel.org
> Subject: Re: [RFC PATCH v2] dmabuf-sync: Introduce buffer synchronization
> framework
>
> On Tue, Jun 18, 2013 at 02:27:40PM +0900, Inki Dae wrote:
> > So I'd like to ask for other DRM maintainers. How do you think about it?
> it
> > seems like that Intel DRM (maintained by Daniel), OMAP DRM (maintained
> by
> > Rob) and GEM CMA helper also have same issue Russell pointed out. I
> think
> > not only the above approach but also the performance is very important.
>
> CMA uses coherent memory to back their buffers, though that might not be
> true of memory obtained from other drivers via dma_buf. Plus, there is
> no support in the CMA helper for exporting or importng these buffers.
>
It's not so. Please see Dave's drm next. recently dmabuf support for the CMA
helper has been merged to there.
> I guess Intel i915 is only used on x86, which is a coherent platform and
> requires no cache maintanence for DMA.
>
> OMAP DRM does not support importing non-DRM buffers buffers back into
Correct. TODO yet.
> DRM. Moreover, it will suffer from the problems I described if any
> attempt is made to write to the buffer after it has been re-imported.
>
> Lastly, I should point out that the dma_buf stuff is really only useful
> when you need to export a dma buffer from one driver and import it into
> another driver - for example to pass data from a camera device driver to
Most people know that.
> a display device driver. It shouldn't be used within a single driver
> as a means of passing buffers between userspace and kernel space.
What I try to do is not really such ugly thing. What I try to do is to
notify that, when CPU tries to access a buffer , to kernel side through
dmabuf interface. So it's not really to send the buffer to kernel.
Thanks,
Inki Dae
^ permalink raw reply
* Re: [PATCH] build some drivers only when compile-testing
From: Felipe Balbi @ 2013-06-18 8:51 UTC (permalink / raw)
To: Michal Marek
Cc: balbi, Jiri Slaby, Jeff Mahoney, Greg Kroah-Hartman, jirislaby,
linux-kernel, Andrew Morton, Linus Torvalds, Alexander Shishkin,
linux-usb, Florian Tobias Schandinat, linux-geode, linux-fbdev,
Richard Cochran, netdev, Ben Hutchings, Keller, Jacob E,
tomi.valkeinen
In-Reply-To: <51C01E04.2050908@suse.cz>
[-- Attachment #1: Type: text/plain, Size: 2279 bytes --]
Hi,
On Tue, Jun 18, 2013 at 10:44:52AM +0200, Michal Marek wrote:
> > On Tue, Jun 18, 2013 at 10:24:40AM +0200, Jiri Slaby wrote:
> >>>>> Sam Ravnborg (the kconfig ex-maintainer) once wrote that
> >>>>> he doesn't want to extend the kconfig language for this
> >>>>> purpose (which I support). That a config option is fine and
> >>>>> sufficient in this case [1]. Except he called the config
> >>>>> option "SHOW_ALL_DRIVERS". Adding the current maintainer to
> >>>>> CCs ;).
> >>>>
> >>>> I agree with Sam. 'depends on XY || COMPILE_TEST' is quite
> >>>> self-explanatory. And even if it's not, you can look up the
> >>>> help text for COMPILE_TEST. With "archdepends on" or
> >>>> "available on", you need to know what to look for to override
> >>>> the dependency.
> >>>
> >>> you will still end up with:
> >>>
> >>> depends on (ARCH_OMAP || ARCH_EXYNOS || ARCH_DAVINCI ||
> >>> ARCH_PPC || ...)
> >>>
> >>> And every now and again that particular line will be updated
> >>> to add another arch dependency.
> >>
> >> But that is perfectly fine *when* the driver is supported on
> >> those archs only.
> >>
> >> And come on, how much often will this "every now and again"
> >> happen? We don't have that much cases where a driver is augmented
> >> to work on another arch or platform. It either works on all of
> >> them => doesn't need COMPILE_TEST, or work on one or two arches
> >> at most.
> >
> > MUSB alone has 8 different arch choices. Before, it used to be that
> > core driver was dependendent on all of them, so whenever someone
> > wanted to build MUSB for another arch, they had to introdude their
> > glue code and modify the dependency of the core driver.
>
> But that you have complex dependencies in some drivers is mostly
> orthogonal to the two choices of syntax, isn't it?
>
> depends on ARCH1 || ARCH2 || .... || ARCH8 || COMPILE_TEST
>
> vs.
>
> archdepends on ARCH1 || ARCH2 || .... || ARCH8
right, but my argument is that I rather not have either. Depend on PCI
if you us PCI, depend on EXTCON if you use extcon, but no driver should
have an ARCH dependency. Specially since it lets people include mach/*
and asm/* headers because "it doesn't break compilation for anyone".
--
balbi
[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 836 bytes --]
^ permalink raw reply
* Re: [PATCH] video: mxsfb: fix color settings for 18bit data bus and 32bpp
From: Hector Palacios @ 2013-06-18 8:45 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <20130618083229.GC15037@lukather>
On 06/18/2013 10:32 AM, maxime.ripard@free-electrons.com wrote:
> Hi Hector,
>
> On Fri, Jun 07, 2013 at 11:02:28AM +0200, maxime.ripard@free-electrons.com wrote:
>> On Fri, Jun 07, 2013 at 10:10:39AM +0200, Hector Palacios wrote:
>>> For a combination of 18bit LCD data bus width and a color
>>> mode of 32bpp, the driver was setting the color mapping to
>>> rgb666, which is wrong, as the color in memory realy has an
>>> rgb888 layout.
>>>
>>> This patch also removes the setting of flag CTRL_DF24 that
>>> makes the driver dimiss the upper 2 bits when handling 32/24bpp
>>> colors in a diplay with 18bit data bus width. This flag made
>>> true color images display wrong in such configurations.
>>>
>>> Finally, the color mapping rgb666 has also been removed as nobody
>>> is using it and high level applications like Qt5 cannot work
>>> with it either.
>>>
>>> Reference: https://lkml.org/lkml/2013/5/23/220
>>> Signed-off-by: Hector Palacios <hector.palacios@digi.com>
>>> Acked-by: Juergen Beisert <jbe@pengutronix.de>
>>
>> Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
>>
>> Please also note that fbdev is now maintained by Jean Christophe
>> Plagniol-Villard (plagnioj@jcrosoft.com, in CC), and that he is away
>> until the 10th of June, so maybe it should be safe to resend it to him
>> after this date.
>
> It seems like Jean-Christophe is back online, maybe you should resend
> him the patch now, it would be great to have it for 3.11.
I just resent it. Thanks for the reminder.
--
Héctor Palacios
Best regards,
--
Hector Palacios
^ permalink raw reply
* Re: [PATCH] build some drivers only when compile-testing
From: Michal Marek @ 2013-06-18 8:44 UTC (permalink / raw)
To: balbi
Cc: Jiri Slaby, Jeff Mahoney, Greg Kroah-Hartman, jirislaby,
linux-kernel, Andrew Morton, Linus Torvalds, Alexander Shishkin,
linux-usb, Florian Tobias Schandinat, linux-geode, linux-fbdev,
Richard Cochran, netdev, Ben Hutchings, Keller, Jacob E,
tomi.valkeinen
In-Reply-To: <20130618083425.GI5461@arwen.pp.htv.fi>
Dne 18.6.2013 10:34, Felipe Balbi napsal(a):
> Hi,
>
> On Tue, Jun 18, 2013 at 10:24:40AM +0200, Jiri Slaby wrote:
>>>>> Sam Ravnborg (the kconfig ex-maintainer) once wrote that
>>>>> he doesn't want to extend the kconfig language for this
>>>>> purpose (which I support). That a config option is fine and
>>>>> sufficient in this case [1]. Except he called the config
>>>>> option "SHOW_ALL_DRIVERS". Adding the current maintainer to
>>>>> CCs ;).
>>>>
>>>> I agree with Sam. 'depends on XY || COMPILE_TEST' is quite
>>>> self-explanatory. And even if it's not, you can look up the
>>>> help text for COMPILE_TEST. With "archdepends on" or
>>>> "available on", you need to know what to look for to override
>>>> the dependency.
>>>
>>> you will still end up with:
>>>
>>> depends on (ARCH_OMAP || ARCH_EXYNOS || ARCH_DAVINCI ||
>>> ARCH_PPC || ...)
>>>
>>> And every now and again that particular line will be updated
>>> to add another arch dependency.
>>
>> But that is perfectly fine *when* the driver is supported on
>> those archs only.
>>
>> And come on, how much often will this "every now and again"
>> happen? We don't have that much cases where a driver is augmented
>> to work on another arch or platform. It either works on all of
>> them => doesn't need COMPILE_TEST, or work on one or two arches
>> at most.
>
> MUSB alone has 8 different arch choices. Before, it used to be that
> core driver was dependendent on all of them, so whenever someone
> wanted to build MUSB for another arch, they had to introdude their
> glue code and modify the dependency of the core driver.
But that you have complex dependencies in some drivers is mostly
orthogonal to the two choices of syntax, isn't it?
depends on ARCH1 || ARCH2 || .... || ARCH8 || COMPILE_TEST
vs.
archdepends on ARCH1 || ARCH2 || .... || ARCH8
Michal
^ permalink raw reply
* [PATCH RESEND] video: mxsfb: fix color settings for 18bit data bus and 32bpp
From: Hector Palacios @ 2013-06-18 8:44 UTC (permalink / raw)
To: linux-arm-kernel
For a combination of 18bit LCD data bus width and a color
mode of 32bpp, the driver was setting the color mapping to
rgb666, which is wrong, as the color in memory realy has an
rgb888 layout.
This patch also removes the setting of flag CTRL_DF24 that
makes the driver dimiss the upper 2 bits when handling 32/24bpp
colors in a diplay with 18bit data bus width. This flag made
true color images display wrong in such configurations.
Finally, the color mapping rgb666 has also been removed as nobody
is using it and high level applications like Qt5 cannot work
with it either.
Reference: https://lkml.org/lkml/2013/5/23/220
Signed-off-by: Hector Palacios <hector.palacios@digi.com>
Acked-by: Juergen Beisert <jbe@pengutronix.de>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
---
drivers/video/mxsfb.c | 26 --------------------------
1 file changed, 26 deletions(-)
diff --git a/drivers/video/mxsfb.c b/drivers/video/mxsfb.c
index 21223d4..d2c5105 100644
--- a/drivers/video/mxsfb.c
+++ b/drivers/video/mxsfb.c
@@ -239,24 +239,6 @@ static const struct fb_bitfield def_rgb565[] = {
}
};
-static const struct fb_bitfield def_rgb666[] = {
- [RED] = {
- .offset = 16,
- .length = 6,
- },
- [GREEN] = {
- .offset = 8,
- .length = 6,
- },
- [BLUE] = {
- .offset = 0,
- .length = 6,
- },
- [TRANSP] = { /* no support for transparency */
- .length = 0,
- }
-};
-
static const struct fb_bitfield def_rgb888[] = {
[RED] = {
.offset = 16,
@@ -309,9 +291,6 @@ static int mxsfb_check_var(struct fb_var_screeninfo *var,
break;
case STMLCDIF_16BIT:
case STMLCDIF_18BIT:
- /* 24 bit to 18 bit mapping */
- rgb = def_rgb666;
- break;
case STMLCDIF_24BIT:
/* real 24 bit */
rgb = def_rgb888;
@@ -453,11 +432,6 @@ static int mxsfb_set_par(struct fb_info *fb_info)
return -EINVAL;
case STMLCDIF_16BIT:
case STMLCDIF_18BIT:
- /* 24 bit to 18 bit mapping */
- ctrl |= CTRL_DF24; /* ignore the upper 2 bits in
- * each colour component
- */
- break;
case STMLCDIF_24BIT:
/* real 24 bit */
break;
--
1.8.3
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