diff options
author | Mario Limonciello <mario.limonciello@amd.com> | 2024-02-02 01:11:15 +0300 |
---|---|---|
committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2024-02-08 16:03:47 +0300 |
commit | 5d389afc1f8fea707225bc2ee64e00d85dab623a (patch) | |
tree | e47bae68760b0d7cf1942d22bf82020df7bdb5fc /drivers/acpi/acpi_video.c | |
parent | 54be6c6c5ae8e0d93a6c4641cb7528eb0b6ba478 (diff) | |
download | linux-5d389afc1f8fea707225bc2ee64e00d85dab623a.tar.xz |
ACPI: video: Handle fetching EDID that is longer than 256 bytes
The ACPI specification allows for an EDID to be up to 512 bytes but
the _DDC EDID fetching code will only try up to 256 bytes.
Modify the code to instead start at 512 bytes and work it's way
down instead.
As _DDC is now called up to 4 times on a machine debugging messages
are noisier than necessary. Decrease from info to debug.
Link: https://uefi.org/htmlspecs/ACPI_Spec_6_4_html/Apx_B_Video_Extensions/output-device-specific-methods.html#ddc-return-the-edid-for-this-device
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
[ rjw: Type mismatch fix, minor whitespace adjustment ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/acpi/acpi_video.c')
-rw-r--r-- | drivers/acpi/acpi_video.c | 28 |
1 files changed, 11 insertions, 17 deletions
diff --git a/drivers/acpi/acpi_video.c b/drivers/acpi/acpi_video.c index 4afdda9db019..1fda30388297 100644 --- a/drivers/acpi/acpi_video.c +++ b/drivers/acpi/acpi_video.c @@ -612,7 +612,7 @@ acpi_video_device_lcd_get_level_current(struct acpi_video_device *device, static int acpi_video_device_EDID(struct acpi_video_device *device, - union acpi_object **edid, ssize_t length) + union acpi_object **edid, int length) { int status; struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL }; @@ -625,13 +625,11 @@ acpi_video_device_EDID(struct acpi_video_device *device, if (!device) return -ENODEV; - if (length == 128) - arg0.integer.value = 1; - else if (length == 256) - arg0.integer.value = 2; - else + if (!length || (length % 128)) return -EINVAL; + arg0.integer.value = length / 128; + status = acpi_evaluate_object(device->dev->handle, "_DDC", &args, &buffer); if (ACPI_FAILURE(status)) return -ENODEV; @@ -641,7 +639,8 @@ acpi_video_device_EDID(struct acpi_video_device *device, if (obj && obj->type == ACPI_TYPE_BUFFER) *edid = obj; else { - acpi_handle_info(device->dev->handle, "Invalid _DDC data\n"); + acpi_handle_debug(device->dev->handle, + "Invalid _DDC data for length %d\n", length); status = -EFAULT; kfree(obj); } @@ -1447,7 +1446,6 @@ int acpi_video_get_edid(struct acpi_device *device, int type, int device_id, for (i = 0; i < video->attached_count; i++) { video_device = video->attached_array[i].bind_info; - length = 256; if (!video_device) continue; @@ -1478,18 +1476,14 @@ int acpi_video_get_edid(struct acpi_device *device, int type, int device_id, continue; } - status = acpi_video_device_EDID(video_device, &buffer, length); - - if (ACPI_FAILURE(status) || !buffer || - buffer->type != ACPI_TYPE_BUFFER) { - length = 128; + for (length = 512; length > 0; length -= 128) { status = acpi_video_device_EDID(video_device, &buffer, length); - if (ACPI_FAILURE(status) || !buffer || - buffer->type != ACPI_TYPE_BUFFER) { - continue; - } + if (ACPI_SUCCESS(status)) + break; } + if (!length) + continue; *edid = buffer->buffer.pointer; return length; |