On 2020-02-21 1:59 p.m., Alex Deucher wrote:
On Fri, Feb 21, 2020 at 1:45 PM Tom St Denis <tom.stdenis@xxxxxxx> wrote:Write a 32-bit value of zero to disable GFXOFF and write a 32-bit value of non-zero to enable GFXOFF. Signed-off-by: Tom St Denis <tom.stdenis@xxxxxxx> --- drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c | 56 +++++++++++++++++++++ 1 file changed, 56 insertions(+) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c index 7379910790c9..3bb74056b9d2 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c @@ -842,6 +842,55 @@ static ssize_t amdgpu_debugfs_gpr_read(struct file *f, char __user *buf, return result; } +/** + * amdgpu_debugfs_regs_gfxoff_write - Enable/disable GFXOFF + * + * @f: open file handle + * @buf: User buffer to write data from + * @size: Number of bytes to write + * @pos: Offset to seek to + * + * Write a 32-bit zero to disable or a 32-bit non-zero to enable + */ +static ssize_t amdgpu_debugfs_gfxoff_write(struct file *f, const char __user *buf, + size_t size, loff_t *pos) +{ + struct amdgpu_device *adev = file_inode(f)->i_private; + ssize_t result = 0; + int r; + + if (size & 0x3 || *pos & 0x3) + return -EINVAL; + + r = pm_runtime_get_sync(adev->ddev->dev);Not really directly related to this patch, but If you are using umr for debugging, we should probably disable runtime pm, otherwise the entire GPU may be powered down between accesses. There is already an interface to do that via the core kernel power subsystem in sysfs. E.g., /sys/class/drm/card0/device/power/control /sys/class/drm/card0/device/power/runtime_status Something else to look at for umr.
We ran into something related to this for UVD/VCE access back in the day. When powered down the MMIO registers are mirrored and accessible but while in transition they are not. So we added a PG flag to the offset in the debugfs entry to flag when we need to take the pm mutex or not.
We don't store the state for when we dynamically turn it off like this so if we get a GPU reset or a power management event (runtime pm or S3), GFXOFF will be re-enabled at that point. This is just for debugging though so: Acked-by: Alex Deucher <alexander.deucher@xxxxxxx>
Good to note. Can I get a R-b from someone though so I can push this out? Tom _______________________________________________ amd-gfx mailing list amd-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/amd-gfx
