On 18/10/2024 23:50, Lyude Paul wrote:
> On Fri, 2024-09-13 at 09:03 +0200, Jocelyn Falempe wrote:
>> Add drm_panic support, for nv50+ cards.
>> It's enough to get the panic screen while running Gnome/Wayland on a
>> GTX 1650.
>> It doesn't support multi-plane or compressed format.
>> Support for other formats and older cards will come later.
>> Tiling is only tested on GTX1650, and might be wrong for other cards.
>>
>> Signed-off-by: Jocelyn Falempe <jfalempe at redhat.com>
>> ---
>>
>> v2:
>> * Rebase and drop already merged patches.
>> * Rework the tiling algorithm, using "swizzle" to compute the offset
>> inside the block.
>>
>> v3:
>> * Fix support for Tesla GPU, which have simpler tiling.
>> * Use nouveau_framebuffer_get_layout() to get the tiling parameters.
>> * Have 2 set_pixel() functions, depending on GPU family.
>>
>> drivers/gpu/drm/nouveau/dispnv50/wndw.c | 139 +++++++++++++++++++++++-
>> 1 file changed, 137 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/nouveau/dispnv50/wndw.c b/drivers/gpu/drm/nouveau/dispnv50/wndw.c
>> index 7a2cceaee6e9..419c5f359711 100644
>> --- a/drivers/gpu/drm/nouveau/dispnv50/wndw.c
>> +++ b/drivers/gpu/drm/nouveau/dispnv50/wndw.c
>> @@ -30,11 +30,16 @@
>> #include <nvhw/class/cl507e.h>
>> #include <nvhw/class/clc37e.h>
>>
>> +#include <linux/iosys-map.h>
>> +
>> #include <drm/drm_atomic.h>
>> #include <drm/drm_atomic_helper.h>
>> #include <drm/drm_blend.h>
>> -#include <drm/drm_gem_atomic_helper.h>
>> #include <drm/drm_fourcc.h>
>> +#include <drm/drm_framebuffer.h>
>> +#include <drm/drm_gem_atomic_helper.h>
>> +#include <drm/drm_panic.h>
>> +#include <drm/ttm/ttm_bo.h>
>>
>> #include "nouveau_bo.h"
>> #include "nouveau_gem.h"
>> @@ -577,6 +582,125 @@ nv50_wndw_prepare_fb(struct drm_plane *plane, struct drm_plane_state *state)
>> return 0;
>> }
>>
>> +#define NV_TILE_BLK_BASE_HEIGHT_TESLA 4 /* In pixel */
>> +#define NV_TILE_BLK_BASE_HEIGHT 8 /* In pixel */
>> +#define NV_TILE_GOB_SIZE 64 /* In bytes */
>> +#define NV_TILE_BLK_WIDTH (NV_TILE_GOB_SIZE / 4) /* For 32 bits pixel */
>
> This was a bit confusing to look at so I had to go and review how some of this
> works. I think it might be better to name this something like:
>
> NV_TILE_GOB_WIDTH_BYTES
>
> Since -technically- the size of a gob is much larger (from nouveau_display.c):
>
> if (drm->client.device.info.family < NV_DEVICE_INFO_V0_FERMI)
> gob_size = 256;
> else
> gob_size = 512;
>
> It's just you're only concerned about the width here.
Ah thanks, actually I wasn't sure why my gob size was different.
The corresponding define in nouveau_display.c is
https://elixir.bootlin.com/linux/v6.11.4/source/drivers/gpu/drm/nouveau/nouveau_display.c#L229
>
>> +
>> +/* Only used by drm_panic get_scanout_buffer() and set_pixel(), so it is
>> + * protected by the drm panic spinlock
>> + */
>> +static u32 nv50_panic_blk_h;
>> +
>> +/* Return the framebuffer offset of the start of the block where pixel(x,y) is */
>> +static u32
>> +nv50_get_block_off(unsigned int x, unsigned int y, unsigned int width)
>> +{
>> + u32 blk_x, blk_y, blk_columns;
>> +
>> + blk_columns = DIV_ROUND_UP(width, NV_TILE_BLK_WIDTH);
>> + blk_x = x / NV_TILE_BLK_WIDTH;
>> + blk_y = y / nv50_panic_blk_h;
>> +
>> + return ((blk_y * blk_columns) + blk_x) * NV_TILE_GOB_SIZE * nv50_panic_blk_h;
>> +}
>> +
>> +/* Turing and later have 2 level of tiles inside the block */
>> +static void
>> +nv50_set_pixel_swizzle(struct drm_scanout_buffer *sb, unsigned int x,
>> + unsigned int y, u32 color)
>> +{
>> + u32 blk_off, off, swizzle;
>> +
>> + blk_off = nv50_get_block_off(x, y, sb->width);
>> +
>> + y = y % nv50_panic_blk_h;
>> +
>> + /* Inside the block, use the fast address swizzle to compute the offset
>> + * For nvidia blocklinear, bit order is yn..y3 x3 y2 x2 y1 y0 x1 x0
>> + */
>> + swizzle = (x & 3) | (y & 3) << 2 | (x & 4) << 2 | (y & 4) << 3;
>> + swizzle |= (x & 8) << 3 | (y >> 3) << 7;
>> + off = blk_off + swizzle * 4;
>> +
>> + iosys_map_wr(&sb->map[0], off, u32, color);
>> +}
>> +
>> +static void
>> +nv50_set_pixel(struct drm_scanout_buffer *sb, unsigned int x, unsigned int y,
>> + u32 color)
>> +{
>> + u32 blk_off, off;
>> +
>> + blk_off = nv50_get_block_off(x, y, sb->width);
>> +
>> + x = x % NV_TILE_BLK_WIDTH;
>> + y = y % nv50_panic_blk_h;
>> + off = blk_off + (x + y * NV_TILE_BLK_WIDTH) * 4;
>> +
>> + iosys_map_wr(&sb->map[0], off, u32, color);
>> +}
>> +
>> +static u32
>> +nv50_get_block_height(u32 tile_mode, u16 chipset)
>> +{
>> + if (chipset < 0xc0)
>> + return NV_TILE_BLK_BASE_HEIGHT_TESLA * (1 << tile_mode);
>> + else
>> + return NV_TILE_BLK_BASE_HEIGHT * (1 << (tile_mode >> 4));
>
> I see this is mentioned above around the definition of NV_TILE_BLK_BASE* - but
> we might want to leave a comment (or rename it) to make it more clear that
> this returns a size in pixels. Since we already have some functions in
> nouveau_display.c regarding similar but different calculations (like
> nouveau_get_height_in_blocks()).
Sure, I will add a comment here.
>
> I was also going to ask if you might be able to reuse some of those functions
> - or have nouveau_display.c reuse some of your code where we verify
> framebuffer sizes. Mainly since we have some functions already for calculating
> width/height of a framebuffer in blocks. But I'm having a bit of trouble
> figuring out if that's possible/relevant, so I'll leave that to you to decide.
Yes, there are some duplicates between the two, and I can't reuse
directly the functions from nouveau_display.c, because they don't fit
what I need here.
If I try to share some code, is it ok to create a dispnv50/tile.[ch] ?
or is there a better place ?
>
>> +}
>> +
>> +static int
>> +nv50_wndw_get_scanout_buffer(struct drm_plane *plane, struct drm_scanout_buffer *sb)
>> +{
>> + struct drm_framebuffer *fb;
>> + struct nouveau_bo *nvbo;
>> + struct nouveau_drm *drm = nouveau_drm(plane->dev);
>> + u16 chipset = drm->client.device.info.chipset;
>> + u32 tile_mode;
>> + u8 kind;
>> +
>> + if (!plane->state || !plane->state->fb)
>> + return -EINVAL;
>> +
>> + fb = plane->state->fb;
>> + nvbo = nouveau_gem_object(fb->obj[0]);
>> +
>> + /* Don't support compressed format, or multiplane yet. */
>> + if (nvbo->comp || fb->format->num_planes != 1)
>> + return -EOPNOTSUPP;
>> +
>> + if (nouveau_bo_map(nvbo)) {
>> + pr_warn("nouveau bo map failed, panic won't be displayed\n");
>
> I think we would want drm_warn() here
sure I will change that.
>
> With the above changes handled/considered -
>
> Reviewed-by: Lyude Paul <lyude at redhat.com>
Thanks a lot, I will send a v4 later this week.
>
> Would be good to have james take another look at this if he's got the time,
> but I think this looks alright :)
>
>> + return -ENOMEM;
>> + }
>> +
>> + if (nvbo->kmap.bo_kmap_type & TTM_BO_MAP_IOMEM_MASK)
>> + iosys_map_set_vaddr_iomem(&sb->map[0], (void __iomem *) nvbo->kmap.virtual);
>> + else
>> + iosys_map_set_vaddr(&sb->map[0], nvbo->kmap.virtual);
>> +
>> + sb->height = fb->height;
>> + sb->width = fb->width;
>> + sb->pitch[0] = fb->pitches[0];
>> + sb->format = fb->format;
>> +
>> + nouveau_framebuffer_get_layout(fb, &tile_mode, &kind);
>> + if (kind) {
>> + /* If tiling is enabled, use set_pixel() to display correctly.
>> + * Only handle 32bits format for now.
>> + */
>> + if (fb->format->cpp[0] != 4)
>> + return -EOPNOTSUPP;
>> + nv50_panic_blk_h = nv50_get_block_height(tile_mode, chipset);
>> + if (chipset >= 0x160)
>> + sb->set_pixel = nv50_set_pixel_swizzle;
>> + else
>> + sb->set_pixel = nv50_set_pixel;
>> + }
>> + return 0;
>> +}
>> +
>> static const struct drm_plane_helper_funcs
>> nv50_wndw_helper = {
>> .prepare_fb = nv50_wndw_prepare_fb,
>> @@ -584,6 +708,14 @@ nv50_wndw_helper = {
>> .atomic_check = nv50_wndw_atomic_check,
>> };
>>
>> +static const struct drm_plane_helper_funcs
>> +nv50_wndw_primary_helper = {
>> + .prepare_fb = nv50_wndw_prepare_fb,
>> + .cleanup_fb = nv50_wndw_cleanup_fb,
>> + .atomic_check = nv50_wndw_atomic_check,
>> + .get_scanout_buffer = nv50_wndw_get_scanout_buffer,
>> +};
>> +
>> static void
>> nv50_wndw_atomic_destroy_state(struct drm_plane *plane,
>> struct drm_plane_state *state)
>> @@ -732,7 +864,10 @@ nv50_wndw_new_(const struct nv50_wndw_func *func, struct drm_device *dev,
>> return ret;
>> }
>>
>> - drm_plane_helper_add(&wndw->plane, &nv50_wndw_helper);
>> + if (type == DRM_PLANE_TYPE_PRIMARY)
>> + drm_plane_helper_add(&wndw->plane, &nv50_wndw_primary_helper);
>> + else
>> + drm_plane_helper_add(&wndw->plane, &nv50_wndw_helper);
>>
>> if (wndw->func->ilut) {
>> ret = nv50_lut_init(disp, mmu, &wndw->ilut);
>