On Sun, Jul 16, 2017 at 12:34:05AM +0100, Brian Potkin wrote: > On Sat 15 Jul 2017 at 19:40:04 +0000, brian m. carlson wrote: > > * Validate data. Nobody is going to print a two-pixel raster image, and > > cups should not accept it as a valid (and in this case, the only > > valid) option. > > cups and cupsfilters have both accepted and fixed past bugs in their > implementation of driverless printing. In some cases cups has made > allowances for deficiencies in a manufacturer's implementaion of IPP > Everywhere. But where does it end? > > Assuming this is a firmware bug, doesn't the vendor (who after all is > using a well defined standard) have the reponsibility, especially if > the issue is drawn to their attention by an affected user? If AirPrint > was involved you could well imagine they would jump to it. I have put in a support request with them. However, I have no way to prove that this actually affects AirPrint, as I don't have any modern Apple devices. I'm pretty sure my alternative is going to be returning the printer. I will say that cups is clearly accepting invalid data. How can a printer have a resolution of 600 dpi and only accept 600x2 raster images? If the printer returned 600x-1 resolution, would cups accept that as well? > > * Use the printer resolution instead of the PWG resolution when > > generating raster images. At the very least, these should be > > resolution options for configuration in addition to the PWG > > resolution. > > Surely the printer resolution is what is returned by an IPP query? > Either that, or it is in a supplied PPD. The printer resolution is indeed returned in an IPP query, as you'll see in the data provided. However, cups only accepts the PWG raster format resolution and ignores the printer resolution. If the driverless printing option provided all three resolution options (600 dpi, 600x2400 dpi, and 600x2 dpi), it would be easy to simply configure the printer to use one of the other options as a default. I do view this aspect as a bug in cups. I should be able to pick any resolution that the printer supports. The vendor does not supply a plain PPD for Linux. They provide a proprietary driver. While that may work for my x86 machines, that will not work for my ARM, MIPS, or PowerPC machines. -- brian m. carlson / brian with sandals: Houston, Texas, US https://www.crustytoothpaste.net/~bmc | My opinion only OpenPGP: https://keybase.io/bk2204
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