| Message ID | 20210716095522.27187-1-ainux.wang@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/ast: Return value when do not get edid | expand |
Am 17.07.21 um 03:14 schrieb Ainux Wang: > Thomas Zimmermann <tzimmermann@suse.de> 于2021年7月16日周五 下午8:00写道： >> >> Hi >> >> Am 16.07.21 um 11:55 schrieb ainux.wang@gmail.com: >>> From: "Ainux.Wang" <ainux.wang@gmail.com> >>> >>> There is should a status when do not get edid. >> >> Well, not really. >> >> So, the problem is that VGA is not hotplug-able. It's supposed to be >> connected when the computer gets switched on. And there's no interface >> for sensing the connection state. >> >> But in practice, the cable can be attached/detached at any time. Reading >> out the EDID is the non-official way for detecting the connection state. >> You either get EDID data or garbage, where the latter is interpreted as >> 'disconnected'. >> >> But really old monitors (maybe mid-90s and before) don't provide EDID >> data. For those, DRM adds standard VGA modes IIRC. And they would likely >> be detected as 'disconnected'. >> >> I'll merge your original patch '(r <= 0)' and anyone who's stuck with >> such an old monitor can probably specify a compatible EDID on the kernel >> command line. >> >> (I'd like to hear other people's opinion about this TBH.) >> >> Best regards >> Thomas >> > Hi， > Thank you for your review and reply, and what is the ‘IIRC’, i do not IIRC stands for 'if I remember correctly' > find it in the > kernel document. > > Best regards > Ainux >>> >>> Signed-off-by: Ainux.Wang <ainux.wang@gmail.com> >>> --- >>> drivers/gpu/drm/ast/ast_mode.c | 4 +++- >>> 1 file changed, 3 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c >>> index e5996ae03c49..05df48b3d223 100644 >>> --- a/drivers/gpu/drm/ast/ast_mode.c >>> +++ b/drivers/gpu/drm/ast/ast_mode.c >>> @@ -1231,8 +1231,10 @@ static int ast_get_modes(struct drm_connector *connector) >>> ret = drm_add_edid_modes(connector, edid); >>> kfree(edid); >>> return ret; >>> - } else >>> + } else { >>> drm_connector_update_edid_property(&ast_connector->base, NULL); >>> + return -ENXIO; >>> + } >>> return 0; >>> } >>> >>> >> >> -- >> Thomas Zimmermann >> Graphics Driver Developer >> SUSE Software Solutions Germany GmbH >> Maxfeldstr. 5, 90409 Nürnberg, Germany >> (HRB 36809, AG Nürnberg) >> Geschäftsführer: Felix Imendörffer >>
diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c index e5996ae03c49..05df48b3d223 100644 --- a/drivers/gpu/drm/ast/ast_mode.c +++ b/drivers/gpu/drm/ast/ast_mode.c @@ -1231,8 +1231,10 @@ static int ast_get_modes(struct drm_connector *connector) ret = drm_add_edid_modes(connector, edid); kfree(edid); return ret; - } else + } else { drm_connector_update_edid_property(&ast_connector->base, NULL); + return -ENXIO; + } return 0; }