Hi,

sorry for being late with the review.

Am 10.11.25 um 17:03 schrieb Ruben Wauters:
As part of the cleanup of gud_probe(), this patch splits off format init
code from gud_probe into it's own function. This makes the code more
compartmentalised and easier to follow, and makes gud_probe() smaller
and also easier to read.

Signed-off-by: Ruben Wauters <[email protected]>
---
  drivers/gpu/drm/gud/gud_drv.c | 167 +++++++++++++++++++---------------
  1 file changed, 93 insertions(+), 74 deletions(-)

diff --git a/drivers/gpu/drm/gud/gud_drv.c b/drivers/gpu/drm/gud/gud_drv.c
index 42135a48d92e..22524601d463 100644
--- a/drivers/gpu/drm/gud/gud_drv.c
+++ b/drivers/gpu/drm/gud/gud_drv.c
@@ -427,84 +427,18 @@ static void gud_free_buffers_and_mutex(void *data)
        mutex_destroy(&gdrm->ctrl_lock);
  }
-static int gud_probe(struct usb_interface *intf, const struct usb_device_id *id)
+static int gud_get_formats(struct gud_device *gdrm, struct device *usb_device, 
u32 *formats,
+                          size_t *max_buffer_size, unsigned int 
*num_formats_ret)

Please don't pass the usb device here. You can get the device from gdrm->drm.dev.

  {
        const struct drm_format_info *xrgb8888_emulation_format = NULL;
        bool rgb565_supported = false, xrgb8888_supported = false;
        unsigned int num_formats_dev, num_formats = 0;
-       struct usb_endpoint_descriptor *bulk_out;
-       struct gud_display_descriptor_req desc;
-       struct device *dev = &intf->dev;
-       size_t max_buffer_size = 0;
-       struct gud_device *gdrm;
-       struct drm_device *drm;
-       struct device *dma_dev;
        u8 *formats_dev;
-       u32 *formats;
+       struct drm_device *drm = &gdrm->drm;
        int ret, i;
- ret = usb_find_bulk_out_endpoint(intf->cur_altsetting, &bulk_out);
-       if (ret)
-               return ret;
-
-       ret = gud_get_display_descriptor(intf, &desc);
-       if (ret) {
-               DRM_DEV_DEBUG_DRIVER(dev, "Not a display interface: ret=%d\n", 
ret);
-               return -ENODEV;
-       }
-
-       if (desc.version > 1) {
-               dev_err(dev, "Protocol version %u is not supported\n", 
desc.version);
-               return -ENODEV;
-       }
-
-       gdrm = devm_drm_dev_alloc(dev, &gud_drm_driver, struct gud_device, drm);
-       if (IS_ERR(gdrm))
-               return PTR_ERR(gdrm);
-
-       drm = &gdrm->drm;
-
-       gdrm->flags = le32_to_cpu(desc.flags);
-       gdrm->compression = desc.compression & GUD_COMPRESSION_LZ4;
-
-       if (gdrm->flags & GUD_DISPLAY_FLAG_FULL_UPDATE && gdrm->compression)
-               return -EINVAL;
-
-       mutex_init(&gdrm->ctrl_lock);
-       mutex_init(&gdrm->damage_lock);
-       INIT_WORK(&gdrm->work, gud_flush_work);
-       gud_clear_damage(gdrm);
-
-       ret = devm_add_action(dev, gud_free_buffers_and_mutex, gdrm);
-       if (ret)
-               return ret;
-
-       usb_set_intfdata(intf, gdrm);
-
-       dma_dev = usb_intf_get_dma_device(intf);
-       if (dma_dev) {
-               drm_dev_set_dma_dev(drm, dma_dev);
-               put_device(dma_dev);
-       } else {
-               dev_warn(dev, "buffer sharing not supported"); /* not an error 
*/
-       }
-
-       /* Mode config init */
-       ret = drmm_mode_config_init(drm);
-       if (ret)
-               return ret;
-
-       drm->mode_config.min_width = le32_to_cpu(desc.min_width);
-       drm->mode_config.max_width = le32_to_cpu(desc.max_width);
-       drm->mode_config.min_height = le32_to_cpu(desc.min_height);
-       drm->mode_config.max_height = le32_to_cpu(desc.max_height);
-       drm->mode_config.funcs = &gud_mode_config_funcs;
-
-       /* Format init */
-       formats_dev = devm_kmalloc(dev, GUD_FORMATS_MAX_NUM, GFP_KERNEL);
-       /* Add room for emulated XRGB8888 */
-       formats = devm_kmalloc_array(dev, GUD_FORMATS_MAX_NUM + 1, 
sizeof(*formats), GFP_KERNEL);
-       if (!formats_dev || !formats)
+       formats_dev = devm_kmalloc(usb_device, GUD_FORMATS_MAX_NUM, GFP_KERNEL);
+       if (!formats_dev)
                return -ENOMEM;
ret = gud_usb_get(gdrm, GUD_REQ_GET_FORMATS, 0, formats_dev, GUD_FORMATS_MAX_NUM);
@@ -555,7 +489,7 @@ static int gud_probe(struct usb_interface *intf, const 
struct usb_device_id *id)
fmt_buf_size = drm_format_info_min_pitch(info, 0, drm->mode_config.max_width) *
                               drm->mode_config.max_height;
-               max_buffer_size = max(max_buffer_size, fmt_buf_size);
+               *max_buffer_size = max(*max_buffer_size, fmt_buf_size);

Rather do this in a separate helper, where you pass in the array of supported formats and it computes max_buffer_size. This way you don't need an output parameter for max_buffer_size.

if (format == GUD_DRM_FORMAT_R1 || format == GUD_DRM_FORMAT_XRGB1111)
                        continue; /* Internal not for userspace */
@@ -564,7 +498,7 @@ static int gud_probe(struct usb_interface *intf, const 
struct usb_device_id *id)
        }
if (!num_formats && !xrgb8888_emulation_format) {
-               dev_err(dev, "No supported pixel formats found\n");
+               dev_err(usb_device, "No supported pixel formats found\n");
                return -EINVAL;
        }
@@ -577,6 +511,92 @@ static int gud_probe(struct usb_interface *intf, const struct usb_device_id *id)
                formats[num_formats++] = DRM_FORMAT_XRGB8888;
        }
+ devm_kfree(usb_device, formats_dev);
+       *num_formats_ret = num_formats;
+
+       return 0;

Instead of 0, you can return num_formats on success.  Together with the change to max_buffer_size, no output parameters will be required.

Best regards
Thomas

+}
+
+static int gud_probe(struct usb_interface *intf, const struct usb_device_id 
*id)
+{
+       unsigned int num_formats = 0;
+       struct usb_endpoint_descriptor *bulk_out;
+       struct gud_display_descriptor_req desc;
+       struct device *dev = &intf->dev;
+       size_t max_buffer_size = 0;
+       struct gud_device *gdrm;
+       struct drm_device *drm;
+       struct device *dma_dev;
+       u32 *formats;
+       int ret;
+
+       ret = usb_find_bulk_out_endpoint(intf->cur_altsetting, &bulk_out);
+       if (ret)
+               return ret;
+
+       ret = gud_get_display_descriptor(intf, &desc);
+       if (ret) {
+               DRM_DEV_DEBUG_DRIVER(dev, "Not a display interface: ret=%d\n", 
ret);
+               return -ENODEV;
+       }
+
+       if (desc.version > 1) {
+               dev_err(dev, "Protocol version %u is not supported\n", 
desc.version);
+               return -ENODEV;
+       }
+
+       gdrm = devm_drm_dev_alloc(dev, &gud_drm_driver, struct gud_device, drm);
+       if (IS_ERR(gdrm))
+               return PTR_ERR(gdrm);
+
+       drm = &gdrm->drm;
+
+       gdrm->flags = le32_to_cpu(desc.flags);
+       gdrm->compression = desc.compression & GUD_COMPRESSION_LZ4;
+
+       if (gdrm->flags & GUD_DISPLAY_FLAG_FULL_UPDATE && gdrm->compression)
+               return -EINVAL;
+
+       mutex_init(&gdrm->ctrl_lock);
+       mutex_init(&gdrm->damage_lock);
+       INIT_WORK(&gdrm->work, gud_flush_work);
+       gud_clear_damage(gdrm);
+
+       ret = devm_add_action(dev, gud_free_buffers_and_mutex, gdrm);
+       if (ret)
+               return ret;
+
+       usb_set_intfdata(intf, gdrm);
+
+       dma_dev = usb_intf_get_dma_device(intf);
+       if (dma_dev) {
+               drm_dev_set_dma_dev(drm, dma_dev);
+               put_device(dma_dev);
+       } else {
+               dev_warn(dev, "buffer sharing not supported"); /* not an error 
*/
+       }
+
+       /* Mode config init */
+       ret = drmm_mode_config_init(drm);
+       if (ret)
+               return ret;
+
+       drm->mode_config.min_width = le32_to_cpu(desc.min_width);
+       drm->mode_config.max_width = le32_to_cpu(desc.max_width);
+       drm->mode_config.min_height = le32_to_cpu(desc.min_height);
+       drm->mode_config.max_height = le32_to_cpu(desc.max_height);
+       drm->mode_config.funcs = &gud_mode_config_funcs;
+
+       /* Format init */
+       /* Add room for emulated XRGB8888 */
+       formats = devm_kmalloc_array(dev, GUD_FORMATS_MAX_NUM + 1, 
sizeof(*formats), GFP_KERNEL);
+       if (!formats)
+               return -ENOMEM;
+
+       ret = gud_get_formats(gdrm, dev, formats, &max_buffer_size, 
&num_formats);
+       if (ret)
+               return ret;
+
        if (desc.max_buffer_size)
                max_buffer_size = le32_to_cpu(desc.max_buffer_size);
        /* Prevent a misbehaving device from allocating loads of RAM. 
4096x4096@XRGB8888 = 64 MB */
@@ -641,7 +661,6 @@ static int gud_probe(struct usb_interface *intf, const 
struct usb_device_id *id)
                return ret;
devm_kfree(dev, formats);
-       devm_kfree(dev, formats_dev);
drm_client_setup(drm, NULL);

--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)


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