| Message ID | 20240201221119.42564-2-mario.limonciello@amd.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add support for fetching EDID from ACPI _DDC | expand |
On Thu, Feb 1, 2024 at 11:11 PM Mario Limonciello <mario.limonciello@amd.com> wrote: > > 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> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> or I can apply it if that's preferred. Thanks! > --- > v1->v2: > * Use for loop for acpi_video_get_edid() > * Use one of Rafael's suggestions for acpi_video_device_EDID() > * Decrease message level too > --- > drivers/acpi/acpi_video.c | 25 +++++++++---------------- > 1 file changed, 9 insertions(+), 16 deletions(-) > > diff --git a/drivers/acpi/acpi_video.c b/drivers/acpi/acpi_video.c > index 4afdda9db019..3bfd013e09d2 100644 > --- a/drivers/acpi/acpi_video.c > +++ b/drivers/acpi/acpi_video.c > @@ -625,12 +625,9 @@ 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)) > @@ -641,7 +638,8 @@ 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 %ld\n", length); > status = -EFAULT; > kfree(obj); > } > @@ -1447,7 +1445,6 @@ 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 +1475,14 @@ 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; > -- > 2.34.1 >
On 2/2/2024 10:07, Rafael J. Wysocki wrote: > On Thu, Feb 1, 2024 at 11:11 PM Mario Limonciello > <mario.limonciello@amd.com> wrote: >> >> 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> > > Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > or I can apply it if that's preferred. Thanks! I think go ahead and apply this one to your -next tree. The rest might take a few weeks to get right and no need to block on this. > > Thanks! > >> --- >> v1->v2: >> * Use for loop for acpi_video_get_edid() >> * Use one of Rafael's suggestions for acpi_video_device_EDID() >> * Decrease message level too >> --- >> drivers/acpi/acpi_video.c | 25 +++++++++---------------- >> 1 file changed, 9 insertions(+), 16 deletions(-) >> >> diff --git a/drivers/acpi/acpi_video.c b/drivers/acpi/acpi_video.c >> index 4afdda9db019..3bfd013e09d2 100644 >> --- a/drivers/acpi/acpi_video.c >> +++ b/drivers/acpi/acpi_video.c >> @@ -625,12 +625,9 @@ 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)) >> @@ -641,7 +638,8 @@ 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 %ld\n", length); >> status = -EFAULT; >> kfree(obj); >> } >> @@ -1447,7 +1445,6 @@ 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 +1475,14 @@ 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; >> -- >> 2.34.1 >>
On Fri, Feb 2, 2024 at 5:09 PM Mario Limonciello <mario.limonciello@amd.com> wrote: > > On 2/2/2024 10:07, Rafael J. Wysocki wrote: > > On Thu, Feb 1, 2024 at 11:11 PM Mario Limonciello > > <mario.limonciello@amd.com> wrote: > >> > >> 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> > > > > Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > > > or I can apply it if that's preferred. > > Thanks! > > I think go ahead and apply this one to your -next tree. Applied now. Barring any issues with it, It will get into linux-next in a couple of days. Thanks!
diff --git a/drivers/acpi/acpi_video.c b/drivers/acpi/acpi_video.c index 4afdda9db019..3bfd013e09d2 100644 --- a/drivers/acpi/acpi_video.c +++ b/drivers/acpi/acpi_video.c @@ -625,12 +625,9 @@ 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)) @@ -641,7 +638,8 @@ 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 %ld\n", length); status = -EFAULT; kfree(obj); } @@ -1447,7 +1445,6 @@ 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 +1475,14 @@ 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;
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> --- v1->v2: * Use for loop for acpi_video_get_edid() * Use one of Rafael's suggestions for acpi_video_device_EDID() * Decrease message level too --- drivers/acpi/acpi_video.c | 25 +++++++++---------------- 1 file changed, 9 insertions(+), 16 deletions(-)