From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Vasut Date: Sun, 10 May 2015 11:49:02 +0200 Subject: [U-Boot] [PATCH 13/16] usb: ohci: Remove unnecessary delays from hc_start and power power-on paths In-Reply-To: <554F2068.2000102@redhat.com> References: <1430862979-4684-1-git-send-email-hdegoede@redhat.com> <201505060101.00835.marex@denx.de> <554F2068.2000102@redhat.com> Message-ID: <201505101149.02374.marex@denx.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Sunday, May 10, 2015 at 11:10:00 AM, Hans de Goede wrote: > Hi, Hi! > On 06-05-15 01:01, Marek Vasut wrote: > > On Tuesday, May 05, 2015 at 11:56:16 PM, Hans de Goede wrote: > >> The common usb_hub code already waits a full second after powering up > >> ports, so there is no need for additional delays inside the hcd code. > >> > >> Signed-off-by: Hans de Goede > > > > This makes a driver depend on the behavior of the subsystem, which might > > change though, right ? Won't this bite us in the future ? > > Well since the usb spec says that we must wait a minimum amount of time > after port power on (exact time is in the hub descriptor) the subsys code > better not change otherwise we would be violating the spec in the future, > also note that we must not only do the wait for root ports but also > for external hub ports, so we can really never drop the wait from the > subsys code, and having a separate wait for just the root hub in the hcd > code will only lead to doing the waiting twice. > > I'll change the commit message to make this clear. Thanks! Best regards, Marek Vasut