On 05/05, Christian König wrote: > On 5/4/25 23:47, Rodrigo Siqueira wrote: > > In the GFX code, there are multiple parsers of the CSB buffer, which can > > be avoided. This data is parsed via get_csb_buffer() in earlier stages, > > and the result can be checked in "adev->gfx.rlc.cs_ptr". To avoid > > re-parser the CSB buffer, this commit introduces a helper that copies > > the CSB buffer into the ring buffer. > > > > Signed-off-by: Rodrigo Siqueira <sique...@igalia.com> > > --- > > drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c | 21 +++++++++++++++++++++ > > drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.h | 4 ++++ > > 2 files changed, 25 insertions(+) > > > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c > > b/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c > > index 8f1a2f7b03c1..dfd48670a0bf 100644 > > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c > > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c > > @@ -2323,6 +2323,27 @@ void amdgpu_gfx_csb_preamble_end(volatile u32 > > *buffer, u32 count) > > buffer[count++] = cpu_to_le32(0); > > } > > > > +/** > > + * amdgpu_gfx_write_csb_to_ring - Write the CSB buffer into the ring > > + * > > + * @ring: Ring reference. > > + * @csb_buffer: CSB buffer. > > + * @csb_size: CSB buffer size. > > + * > > + * Usually, the adev->gfx.rlc.cs_ptr field is filled in earlier stages via > > + * get_csb_buffer(). This function just gets the CSB buffer and fills it > > in the > > + * ring buffer. > > + */ > > +void amdgpu_gfx_write_csb_to_ring(struct amdgpu_ring *ring, > > We already have the amdgpu_ring_write_multiple() function for exactly that.
I'll prepare a V2 that uses amdgpu_ring_write_multiple(). > > > + volatile u32 *csb_buffer, > > Please drop volatile from all pointers inside the kernel and point me out if > you still find some in existing code. > > They are nearly always used incorrectly, see here > https://docs.kernel.org/process/volatile-considered-harmful.html Thanks for the link. I'll make a separate patchset for that. Thanks Siqueira > > Thanks, > Christian. > > > > + u32 csb_size) > > > > > > +{ > > + int i; > > + > > + for (i = 0; i < csb_size; i++) > > + amdgpu_ring_write(ring, csb_buffer[i]); > > +} > > + > > /* > > * debugfs for to enable/disable gfx job submission to specific core. > > */ > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.h > > b/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.h > > index 08f268dab8f5..ce684c3d3d89 100644 > > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.h > > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.h > > @@ -646,6 +646,10 @@ u32 amdgpu_gfx_csb_preamble_start(volatile u32 > > *buffer); > > u32 amdgpu_gfx_csb_data_parser(struct amdgpu_device *adev, volatile u32 > > *buffer, u32 count); > > void amdgpu_gfx_csb_preamble_end(volatile u32 *buffer, u32 count); > > > > +void amdgpu_gfx_write_csb_to_ring(struct amdgpu_ring *ring, > > + volatile u32 *csb_buffer, > > + u32 csb_size); > > + > > void amdgpu_debugfs_gfx_sched_mask_init(struct amdgpu_device *adev); > > void amdgpu_debugfs_compute_sched_mask_init(struct amdgpu_device *adev); > > > -- Rodrigo Siqueira
