The problem here is that "unsigned i" is always greater than or equal to
zero. These loops mostly have a second check for "(i == 0)" so only the
last two are actually buggy. The rest is just cleanup.
Bug 1: kv_force_dpm_highest() doesn't have an "(i == 0)" check so it's
a potential forever loop.
Bug 2: In kv_get_sleep_divider_id_from_clock() there is a typo and the
test is reversed "<=" vs ">" so we never enter the loop. That means
normally we return KV_MAX_DEEPSLEEP_DIVIDER_ID (5). …
[View More] The return value
from here is saved in ->DeepSleepDivId and I wasn't able to determine
how that is used. This is a static checker fix and I have not tested
it.
Signed-off-by: Dan Carpenter <dan.carpenter(a)oracle.com>
---
I considered making "i" signed but that doesn't actually change anything
because the tests have to end on zero anyway.
diff --git a/drivers/gpu/drm/radeon/kv_dpm.c b/drivers/gpu/drm/radeon/kv_dpm.c
index ecd6080..c499daf 100644
--- a/drivers/gpu/drm/radeon/kv_dpm.c
+++ b/drivers/gpu/drm/radeon/kv_dpm.c
@@ -667,9 +667,8 @@ static int kv_program_bootup_state(struct radeon_device *rdev)
&rdev->pm.dpm.dyn_state.vddc_dependency_on_sclk;
if (table && table->count) {
- for (i = pi->graphics_dpm_level_count - 1; i >= 0; i--) {
- if ((table->entries[i].clk == pi->boot_pl.sclk) ||
- (i == 0))
+ for (i = pi->graphics_dpm_level_count - 1; i > 0; i--) {
+ if (table->entries[i].clk == pi->boot_pl.sclk)
break;
}
@@ -682,9 +681,8 @@ static int kv_program_bootup_state(struct radeon_device *rdev)
if (table->num_max_dpm_entries == 0)
return -EINVAL;
- for (i = pi->graphics_dpm_level_count - 1; i >= 0; i--) {
- if ((table->entries[i].sclk_frequency == pi->boot_pl.sclk) ||
- (i == 0))
+ for (i = pi->graphics_dpm_level_count - 1; i > 0; i--) {
+ if (table->entries[i].sclk_frequency == pi->boot_pl.sclk)
break;
}
@@ -1588,13 +1586,11 @@ static void kv_set_valid_clock_range(struct radeon_device *rdev,
}
}
- for (i = pi->graphics_dpm_level_count - 1; i >= 0; i--) {
- if ((table->entries[i].clk <= new_ps->levels[new_ps->num_levels -1].sclk) ||
- (i == 0)) {
- pi->highest_valid = i;
+ for (i = pi->graphics_dpm_level_count - 1; i > 0; i--) {
+ if (table->entries[i].clk <= new_ps->levels[new_ps->num_levels - 1].sclk)
break;
- }
}
+ pi->highest_valid = i;
if (pi->lowest_valid > pi->highest_valid) {
if ((new_ps->levels[0].sclk - table->entries[pi->highest_valid].clk) >
@@ -1615,14 +1611,12 @@ static void kv_set_valid_clock_range(struct radeon_device *rdev,
}
}
- for (i = pi->graphics_dpm_level_count - 1; i >= 0; i--) {
+ for (i = pi->graphics_dpm_level_count - 1; i > 0; i--) {
if (table->entries[i].sclk_frequency <=
- new_ps->levels[new_ps->num_levels - 1].sclk ||
- i == 0) {
- pi->highest_valid = i;
+ new_ps->levels[new_ps->num_levels - 1].sclk)
break;
- }
}
+ pi->highest_valid = i;
if (pi->lowest_valid > pi->highest_valid) {
if ((new_ps->levels[0].sclk -
@@ -1871,7 +1865,7 @@ static int kv_force_dpm_highest(struct radeon_device *rdev)
if (ret)
return ret;
- for (i = SMU7_MAX_LEVELS_GRAPHICS - 1; i >= 0; i--) {
+ for (i = SMU7_MAX_LEVELS_GRAPHICS - 1; i > 0; i--) {
if (enable_mask & (1 << i))
break;
}
@@ -1911,9 +1905,9 @@ static u8 kv_get_sleep_divider_id_from_clock(struct radeon_device *rdev,
if (!pi->caps_sclk_ds)
return 0;
- for (i = KV_MAX_DEEPSLEEP_DIVIDER_ID; i <= 0; i--) {
+ for (i = KV_MAX_DEEPSLEEP_DIVIDER_ID; i > 0; i--) {
temp = sclk / sumo_get_sleep_divider_from_id(i);
- if ((temp >= min) || (i == 0))
+ if (temp >= min)
break;
}
[View Less]
Each dma-buf has an associated size and it's reasonable for userspace
to want to know what it is.
Since userspace already has an fd, expose the size using the
size = lseek(fd, SEEK_END, 0); lseek(fd, SEEK_CUR, 0);
idiom.
v2: Added Daniel's sugeested documentation, with minor fixups
Signed-off-by: Christopher James Halse Rogers <christopher.halse.rogers(a)canonical.com>
Reviewed-by: Daniel Vetter <daniel.vetter(a)ffwll.ch>
Tested-by: Daniel Vetter <daniel.vetter(a)ffwll.ch>
-…
[View More]--
Documentation/dma-buf-sharing.txt | 12 ++++++++++++
drivers/base/dma-buf.c | 28 ++++++++++++++++++++++++++++
2 files changed, 40 insertions(+)
diff --git a/Documentation/dma-buf-sharing.txt b/Documentation/dma-buf-sharing.txt
index 0b23261..849e982 100644
--- a/Documentation/dma-buf-sharing.txt
+++ b/Documentation/dma-buf-sharing.txt
@@ -407,6 +407,18 @@ Being able to mmap an export dma-buf buffer object has 2 main use-cases:
interesting ways depending upong the exporter (if userspace starts depending
upon this implicit synchronization).
+Other Interfaces Exposed to Userspace on the dma-buf FD
+------------------------------------------------------
+
+- Since kernel 3.12 the dma-buf FD supports the llseek system call, but only
+ with offset=0 and whence=SEEK_END|SEEK_SET. SEEK_SET is supported to allow
+ the usual size discover pattern size = SEEK_END(0); SEEK_SET(0). Every other
+ llseek operation will report -EINVAL.
+
+ If llseek on dma-buf FDs isn't support the kernel will report -ESPIPE for all
+ cases. Userspace can use this to detect support for discovering the dma-buf
+ size using llseek.
+
Miscellaneous notes
-------------------
diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c
index 6687ba7..c33a857 100644
--- a/drivers/base/dma-buf.c
+++ b/drivers/base/dma-buf.c
@@ -77,9 +77,36 @@ static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
return dmabuf->ops->mmap(dmabuf, vma);
}
+static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence)
+{
+ struct dma_buf *dmabuf;
+ loff_t base;
+
+ if (!is_dma_buf_file(file))
+ return -EBADF;
+
+ dmabuf = file->private_data;
+
+ /* only support discovering the end of the buffer,
+ but also allow SEEK_SET to maintain the idiomatic
+ SEEK_END(0), SEEK_CUR(0) pattern */
+ if (whence == SEEK_END)
+ base = dmabuf->size;
+ else if (whence == SEEK_SET)
+ base = 0;
+ else
+ return -EINVAL;
+
+ if (offset != 0)
+ return -EINVAL;
+
+ return base + offset;
+}
+
static const struct file_operations dma_buf_fops = {
.release = dma_buf_release,
.mmap = dma_buf_mmap_internal,
+ .llseek = dma_buf_llseek,
};
/*
@@ -133,6 +160,7 @@ struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops,
dmabuf->exp_name = exp_name;
file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf, flags);
+ file->f_mode |= FMODE_LSEEK;
dmabuf->file = file;
--
1.8.3.2
[View Less]
https://bugzilla.kernel.org/show_bug.cgi?id=60827
--- Comment #3 from Alex Deucher <alexdeucher(a)gmail.com> ---
You might also try a newer kernel. It looks like the uvd ring that is failing
to resume properly. There are a number of fixes for suspend/resume related
problems with uvd in 3.11 (most of which should end up in stable).
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