Hi Am 12.08.22 um 20:19 schrieb Sam Ravnborg:
Hi Thomas, On Wed, Aug 10, 2022 at 01:20:53PM +0200, Thomas Zimmermann wrote:Add drm_fb_build_fourcc_list() function that builds a list of supported formats from native and emulated ones. Helpful for all drivers that do format conversion as part of their plane updates. Update current caller. Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>A few comments in the following. Consider to add the warning and with it added or not: Reviewed-by: Sam Ravnborg <sam@xxxxxxxxxxxx>--- drivers/gpu/drm/drm_format_helper.c | 94 +++++++++++++++++++++++++++++ drivers/gpu/drm/tiny/simpledrm.c | 47 ++------------- include/drm/drm_format_helper.h | 11 +++- 3 files changed, 109 insertions(+), 43 deletions(-) diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c index 56642816fdff..dca5531615f3 100644 --- a/drivers/gpu/drm/drm_format_helper.c +++ b/drivers/gpu/drm/drm_format_helper.c @@ -793,3 +793,97 @@ void drm_fb_xrgb8888_to_mono(struct iosys_map *dst, const unsigned int *dst_pitc kfree(src32); } EXPORT_SYMBOL(drm_fb_xrgb8888_to_mono); + +static bool is_listed_fourcc(const uint32_t *fourccs, size_t nfourccs, uint32_t fourcc) +{ + const uint32_t *fourccs_end = fourccs + nfourccs; + + while (fourccs < fourccs_end) { + if (*fourccs == fourcc) + return true; + ++fourccs; + } + return false; +} + +/** + * drm_fb_build_fourcc_list - Filters a list of supported color formats against + * the device's native formats + * @dev: DRM device + * @native_fourccs: 4CC codes of natively supported color formats + * @native_nfourccs: The number of entries in @native_fourccs + * @extra_fourccs: 4CC codes of additionally supported color formats + * @extra_nfourccs: The number of entries in @extra_fourccs + * @fourccs_out: Returns 4CC codes of supported color formats + * @nfourccs_out: The number of available entries in @fourccs_out + * + * This function create a list of supported color format from natively + * supported formats and the emulated formats. *Stray '*' at the end of the line.+ * At a minimum, most userspace programs expect at least support for + * XRGB8888 on the primary plane. Devices that have to emulate the + * format, and possibly others, can use drm_fb_build_fourcc_list() to + * create a list of supported color formats. The returned list can + * be handed over to drm_universal_plane_init() et al. Native formats + * will go before emulated formats. Other heuristics might be applied + * to optimize the order. Formats near the beginning of the list are + * usually preferred over formats near the end of the list. + * + * Returns: + * The number of color-formats 4CC codes returned in @fourccs_out. + */ +size_t drm_fb_build_fourcc_list(struct drm_device *dev, + const uint32_t *native_fourccs, size_t native_nfourccs, + const uint32_t *extra_fourccs, size_t extra_nfourccs, + uint32_t *fourccs_out, size_t nfourccs_out)drm_fourcc.c uses the type u32 for fourcc codes, why no go with the same here? I wish we had a better way to express that we have a list of fourcc codes, for example using list_head. But it is a bad mismatch with the current drm_universal_plane_init() implementation.
I've changed the code to u32. struct list_head is somewhat overhead-ish, but I'd like to see a 'fourcc_t' typedef of the u32.
The format negotiation operation in the bridges could benefit too.+{ + uint32_t *fourccs = fourccs_out; + const uint32_t *fourccs_end = fourccs_out + nfourccs_out; + bool found_native = false; + size_t nfourccs, i; + + /* native formats go first */ +Drop extra line, capital start+ nfourccs = min_t(size_t, native_nfourccs, nfourccs_out); + + for (i = 0; i < nfourccs; ++i) { + uint32_t fourcc = native_fourccs[i]; + + drm_dbg_kms(dev, "adding native format %p4cc\n", &fourcc); + + if (!found_native) + found_native = is_listed_fourcc(extra_fourccs, extra_nfourccs, fourcc); + *fourccs = fourcc; + ++fourccs; + } + + /* + * The plane's atomic_update helper converts the framebuffer's color format + * to the native format when copying them to device memory. + * + * If there is not a single format supported by both, device and + * plane, the native formats are likely not supported by the conversion + * helpers. Therefore *only* support the native formats and add a + * conversion helper ASAP. + */Despite the nice comment I had to think twice. In the end I agree with this.+ if (!found_native) { + drm_warn(dev, "format conversion helpers required to add extra formats\n"); + goto out; + } + + /* extra formats go second */ +Drop extra line, capital start.+ nfourccs = min_t(size_t, extra_nfourccs, fourccs_end - fourccs); + + for (i = 0; i < nfourccs; ++i) { + uint32_t fourcc = extra_fourccs[i]; + + if (is_listed_fourcc(native_fourccs, native_nfourccs, fourcc)) + continue; /* native formats already went first */ + *fourccs = fourcc; + ++fourccs; + } + +out: + return fourccs - fourccs_out; +}It would be prudent to warn if the supplied fourccs_out array is too small to the provided input formats. simpledrm is about to hit the limit.
Good idea. I've added a warning. Best regards Thomas
+EXPORT_SYMBOL(drm_fb_build_fourcc_list); diff --git a/drivers/gpu/drm/tiny/simpledrm.c b/drivers/gpu/drm/tiny/simpledrm.c index cc509154b296..79c9fd6bedf0 100644 --- a/drivers/gpu/drm/tiny/simpledrm.c +++ b/drivers/gpu/drm/tiny/simpledrm.c @@ -644,45 +644,6 @@ static struct drm_display_mode simpledrm_mode(unsigned int width, return mode; }-static const uint32_t *simpledrm_device_formats(struct simpledrm_device *sdev,- size_t *nformats_out) -{ - struct drm_device *dev = &sdev->dev; - size_t i; - - if (sdev->nformats) - goto out; /* don't rebuild list on recurring calls */ - - /* native format goes first */ - sdev->formats[0] = sdev->format->format; - sdev->nformats = 1; - - /* default formats go second */ - for (i = 0; i < ARRAY_SIZE(simpledrm_primary_plane_formats); ++i) { - if (simpledrm_primary_plane_formats[i] == sdev->format->format) - continue; /* native format already went first */ - sdev->formats[sdev->nformats] = simpledrm_primary_plane_formats[i]; - sdev->nformats++; - } - - /* - * TODO: The simpledrm driver converts framebuffers to the native - * format when copying them to device memory. If there are more - * formats listed than supported by the driver, the native format - * is not supported by the conversion helpers. Therefore *only* - * support the native format and add a conversion helper ASAP. - */ - if (drm_WARN_ONCE(dev, i != sdev->nformats, - "format conversion helpers required for %p4cc", - &sdev->format->format)) { - sdev->nformats = 1; - } - -out: - *nformats_out = sdev->nformats; - return sdev->formats; -} - static struct simpledrm_device *simpledrm_device_create(struct drm_driver *drv, struct platform_device *pdev) { @@ -699,7 +660,6 @@ static struct simpledrm_device *simpledrm_device_create(struct drm_driver *drv, struct drm_encoder *encoder; struct drm_connector *connector; unsigned long max_width, max_height; - const uint32_t *formats; size_t nformats; int ret;@@ -811,11 +771,14 @@ static struct simpledrm_device *simpledrm_device_create(struct drm_driver *drv, /* Primary plane */ - formats = simpledrm_device_formats(sdev, &nformats);+ nformats = drm_fb_build_fourcc_list(dev, &format->format, 1, + simpledrm_primary_plane_formats, + ARRAY_SIZE(simpledrm_primary_plane_formats), + sdev->formats, ARRAY_SIZE(sdev->formats));simpledrm_primary_plane_formats is 6 long, with a todo to add 2 more. So the current array of 8 in sdev->formats is big enough for now.primary_plane = &sdev->primary_plane;ret = drm_universal_plane_init(dev, primary_plane, 0, &simpledrm_primary_plane_funcs, - formats, nformats, + sdev->formats, nformats, simpledrm_primary_plane_format_modifiers, DRM_PLANE_TYPE_PRIMARY, NULL); if (ret) diff --git a/include/drm/drm_format_helper.h b/include/drm/drm_format_helper.h index caa181194335..33278870e0d8 100644 --- a/include/drm/drm_format_helper.h +++ b/include/drm/drm_format_helper.h @@ -6,11 +6,15 @@ #ifndef __LINUX_DRM_FORMAT_HELPER_H #define __LINUX_DRM_FORMAT_HELPER_H-struct iosys_map;+#include <linux/types.h> + +struct drm_device; struct drm_format_info; struct drm_framebuffer; struct drm_rect;+struct iosys_map;+ unsigned int drm_fb_clip_offset(unsigned int pitch, const struct drm_format_info *format, const struct drm_rect *clip);@@ -44,4 +48,9 @@ void drm_fb_xrgb8888_to_mono(struct iosys_map *dst, const unsigned int *dst_pitcconst struct iosys_map *src, const struct drm_framebuffer *fb, const struct drm_rect *clip);+size_t drm_fb_build_fourcc_list(struct drm_device *dev,+ const uint32_t *native_fourccs, size_t native_nfourccs, + const uint32_t *extra_fourccs, size_t extra_nfourccs, + uint32_t *fourccs_out, size_t nfourccs_out); + #endif /* __LINUX_DRM_FORMAT_HELPER_H */ -- 2.37.1
-- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Maxfeldstr. 5, 90409 Nürnberg, Germany (HRB 36809, AG Nürnberg) Geschäftsführer: Ivo Totev
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