Hi

Am 23.09.24 um 06:35 schrieb Dmitry Baryshkov:
On Mon, Sep 02, 2024 at 12:53:40PM GMT, Thomas Zimmermann wrote:
Implement a read function for struct drm_edid and read the EDID data
with drm_edit_read_custom(). Update the connector data accordingly.

The EDID data comes from the emulator itself and the connector stores
a copy in its EDID property. The drm_edid field in struct bochs_device
is therefore not required. Remove it.

If qemu provides no EDID data, install default display modes as before.

Signed-off-by: Thomas Zimmermann <[email protected]>
Acked-by: Gerd Hoffmann <[email protected]>
---
  drivers/gpu/drm/tiny/bochs.c | 48 +++++++++++++++++-------------------
  1 file changed, 22 insertions(+), 26 deletions(-)

diff --git a/drivers/gpu/drm/tiny/bochs.c b/drivers/gpu/drm/tiny/bochs.c
index 47a45a14306c..197fc00b373f 100644
--- a/drivers/gpu/drm/tiny/bochs.c
+++ b/drivers/gpu/drm/tiny/bochs.c
@@ -85,7 +85,6 @@ struct bochs_device {
        u16 yres_virtual;
        u32 stride;
        u32 bpp;
-       const struct drm_edid *drm_edid;
/* drm */
        struct drm_device *dev;
@@ -172,12 +171,14 @@ static void bochs_hw_set_little_endian(struct 
bochs_device *bochs)
  #define bochs_hw_set_native_endian(_b) bochs_hw_set_little_endian(_b)
  #endif
-static int bochs_get_edid_block(void *data, u8 *buf,
-                               unsigned int block, size_t len)
+static int bochs_get_edid_block(void *data, u8 *buf, unsigned int block, 
size_t len)
  {
        struct bochs_device *bochs = data;
        size_t i, start = block * EDID_LENGTH;
+ if (!bochs->mmio)
+               return -1;
+
        if (start + len > 0x400 /* vga register offset */)
                return -1;
@@ -187,25 +188,20 @@ static int bochs_get_edid_block(void *data, u8 *buf,
        return 0;
  }
-static int bochs_hw_load_edid(struct bochs_device *bochs)
+static const struct drm_edid *bochs_hw_read_edid(struct drm_connector 
*connector)
  {
+       struct drm_device *dev = connector->dev;
+       struct bochs_device *bochs = dev->dev_private;
        u8 header[8];
- if (!bochs->mmio)
-               return -1;
-
        /* check header to detect whenever edid support is enabled in qemu */
        bochs_get_edid_block(bochs, header, 0, ARRAY_SIZE(header));
        if (drm_edid_header_is_valid(header) != 8)
I understand that you probably don't want to change the behaviour of the
driver, but maybe it's better to check drm_edid_read_custom return
value? Bochs, amdgpu and radeon are the only drivers that call
drm_edid_header_is_valid().

The nearby comment indicates that EDID support might not be present in qemu. But drm_edid_read_custom() warns in this case, even though it's a legal state. Hence the test.

Best regards
Thomas


-               return -1;
+               return NULL;

--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)

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