search for: drm_dp_connection_status_notifi

The names for these functions are rather confusing. drm_dp_add_port() sounds like a function that would simply create a port and add it to a topology, and do nothing more. Similarly, drm_dp_update_port() would be assumed to be the function that should be used to update port information after initial creation. While those assumptions are currently correct in how these functions are used, a quick

This probably hasn't caused any problems up until now since it's probably nearly impossible to encounter this in the wild, however if we were to receive a connection status notification from the MST hub after resume while we're in the middle of reprobing the link addresses for a topology then there's a much larger chance that a port could have changed from being an output port to

On Tue, Sep 03, 2019 at 04:45:54PM -0400, Lyude Paul wrote: > Since we're going to be implementing suspend/resume reprobing very soon, > we need to make sure we are extra careful to ensure that our locking > actually protects the topology state where we expect it to. Turns out > this isn't the case with drm_dp_port_setup_pdt() and > drm_dp_port_teardown_pdt(), both of which

On Tue, Sep 03, 2019 at 04:45:58PM -0400, Lyude Paul wrote: > Yes-you read that right. Currently there is literally no locking in > place for any of the drm_dp_mst_port struct members that can be modified > in response to a link address response, or a connection status response. > Which literally means if we're unlucky enough to have any sort of > hotplugging event happen before

Once upon a time, hotplugging devices on MST branches actually worked in DRM. Now, it only works in amdgpu (likely because of how it's hotplug handlers are implemented). On both i915 and nouveau, hotplug notifications from MST branches are noticed - but trying to respond to them causes messaging timeouts and causes the whole topology state to go out of sync with reality, usually resulting in

Once upon a time, hotplugging devices on MST branches actually worked in DRM. Now, it only works in amdgpu (likely because of how it's hotplug handlers are implemented). On both i915 and nouveau, hotplug notifications from MST branches are noticed - but trying to respond to them causes messaging timeouts and causes the whole topology state to go out of sync with reality, usually resulting in

Since we're going to be implementing suspend/resume reprobing very soon, we need to make sure we are extra careful to ensure that our locking actually protects the topology state where we expect it to. Turns out this isn't the case with drm_dp_port_setup_pdt() and drm_dp_port_teardown_pdt(), both of which change port->mstb without grabbing &mgr->lock. Additionally, since most

Since we're going to be implementing suspend/resume reprobing very soon, we need to make sure we are extra careful to ensure that our locking actually protects the topology state where we expect it to. Turns out this isn't the case with drm_dp_port_setup_pdt() and drm_dp_port_teardown_pdt(), both of which change port->mstb without grabbing &mgr->lock. Additionally, since most

Yes-you read that right. Currently there is literally no locking in place for any of the drm_dp_mst_port struct members that can be modified in response to a link address response, or a connection status response. Which literally means if we're unlucky enough to have any sort of hotplugging event happen before we're finished with reprobing link addresses, we'll race and the contents of

On Wed, 2019-09-25 at 15:27 -0400, Sean Paul wrote: > On Tue, Sep 03, 2019 at 04:45:54PM -0400, Lyude Paul wrote: > > Since we're going to be implementing suspend/resume reprobing very soon, > > we need to make sure we are extra careful to ensure that our locking > > actually protects the topology state where we expect it to. Turns out > > this isn't the case

This is the large series for adding MST suspend/resume reprobing that I've been working on for quite a while now. In addition, I: - Refactored and cleaned up any code I ended up digging through in the process of understanding how some parts of these helpers worked. - Added some debugging tools along the way that I ended up needing to figure out some issues in my own code Note that

This is a complicated one. Essentially, there's currently a problem in the MST core that hasn't really caused any issues that we're aware of (emphasis on "that we're aware of"): locking. When we go through and probe the link addresses and path resources in a topology, we hold no locks when updating ports with said information. The members I'm referring to in

This is the final portion of the large series for adding MST suspend/resume reprobing that I've been working on for quite a while now. In addition, I: * Refactored and cleaned up any code I ended up digging through in the process of understanding how some parts of these helpers worked. * Added some debugging tools along the way that I ended up needing to figure out some issues in my own